sequelize.js 50.5 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365
'use strict';

const url = require('url');
const path = require('path');
const retry = require('retry-as-promised');
const _ = require('lodash');

const Utils = require('./utils');
const Model = require('./model');
const DataTypes = require('./data-types');
const Deferrable = require('./deferrable');
const ModelManager = require('./model-manager');
const Transaction = require('./transaction');
const QueryTypes = require('./query-types');
const TableHints = require('./table-hints');
const IndexHints = require('./index-hints');
const sequelizeErrors = require('./errors');
const Hooks = require('./hooks');
const Association = require('./associations/index');
const Validator = require('./utils/validator-extras').validator;
const Op = require('./operators');
const deprecations = require('./utils/deprecations');

/**
 * This is the main class, the entry point to sequelize.
 */
class Sequelize {
  /**
   * Instantiate sequelize with name of database, username and password.
   *
   * @example
   * // without password / with blank password
   * const sequelize = new Sequelize('database', 'username', null, {
   *   dialect: 'mysql'
   * })
   *
   * // with password and options
   * const sequelize = new Sequelize('my_database', 'john', 'doe', {
   *   dialect: 'postgres'
   * })
   *
   * // with database, username, and password in the options object
   * const sequelize = new Sequelize({ database, username, password, dialect: 'mssql' });
   *
   * // with uri
   * const sequelize = new Sequelize('mysql://localhost:3306/database', {})
   *
   * // option examples
   * const sequelize = new Sequelize('database', 'username', 'password', {
   *   // the sql dialect of the database
   *   // currently supported: 'mysql', 'sqlite', 'postgres', 'mssql'
   *   dialect: 'mysql',
   *
   *   // custom host; default: localhost
   *   host: 'my.server.tld',
   *   // for postgres, you can also specify an absolute path to a directory
   *   // containing a UNIX socket to connect over
   *   // host: '/sockets/psql_sockets'.
   *
   *   // custom port; default: dialect default
   *   port: 12345,
   *
   *   // custom protocol; default: 'tcp'
   *   // postgres only, useful for Heroku
   *   protocol: null,
   *
   *   // disable logging or provide a custom logging function; default: console.log
   *   logging: false,
   *
   *   // you can also pass any dialect options to the underlying dialect library
   *   // - default is empty
   *   // - currently supported: 'mysql', 'postgres', 'mssql'
   *   dialectOptions: {
   *     socketPath: '/Applications/MAMP/tmp/mysql/mysql.sock',
   *     supportBigNumbers: true,
   *     bigNumberStrings: true
   *   },
   *
   *   // the storage engine for sqlite
   *   // - default ':memory:'
   *   storage: 'path/to/database.sqlite',
   *
   *   // disable inserting undefined values as NULL
   *   // - default: false
   *   omitNull: true,
   *
   *   // a flag for using a native library or not.
   *   // in the case of 'pg' -- set this to true will allow SSL support
   *   // - default: false
   *   native: true,
   *
   *   // Specify options, which are used when sequelize.define is called.
   *   // The following example:
   *   //   define: { timestamps: false }
   *   // is basically the same as:
   *   //   Model.init(attributes, { timestamps: false });
   *   //   sequelize.define(name, attributes, { timestamps: false });
   *   // so defining the timestamps for each model will be not necessary
   *   define: {
   *     underscored: false,
   *     freezeTableName: false,
   *     charset: 'utf8',
   *     dialectOptions: {
   *       collate: 'utf8_general_ci'
   *     },
   *     timestamps: true
   *   },
   *
   *   // similar for sync: you can define this to always force sync for models
   *   sync: { force: true },
   *
   *   // pool configuration used to pool database connections
   *   pool: {
   *     max: 5,
   *     idle: 30000,
   *     acquire: 60000,
   *   },
   *
   *   // isolation level of each transaction
   *   // defaults to dialect default
   *   isolationLevel: Transaction.ISOLATION_LEVELS.REPEATABLE_READ
   * })
   *
   * @param {string}   [database] The name of the database
   * @param {string}   [username=null] The username which is used to authenticate against the database.
   * @param {string}   [password=null] The password which is used to authenticate against the database. Supports SQLCipher encryption for SQLite.
   * @param {object}   [options={}] An object with options.
   * @param {string}   [options.host='localhost'] The host of the relational database.
   * @param {number}   [options.port=] The port of the relational database.
   * @param {string}   [options.username=null] The username which is used to authenticate against the database.
   * @param {string}   [options.password=null] The password which is used to authenticate against the database.
   * @param {string}   [options.database=null] The name of the database
   * @param {string}   [options.dialect] The dialect of the database you are connecting to. One of mysql, postgres, sqlite and mssql.
   * @param {string}   [options.dialectModule=null] If specified, use this dialect library. For example, if you want to use pg.js instead of pg when connecting to a pg database, you should specify 'require("pg.js")' here
   * @param {string}   [options.dialectModulePath=null] If specified, load the dialect library from this path. For example, if you want to use pg.js instead of pg when connecting to a pg database, you should specify '/path/to/pg.js' here
   * @param {object}   [options.dialectOptions] An object of additional options, which are passed directly to the connection library
   * @param {string}   [options.storage] Only used by sqlite. Defaults to ':memory:'
   * @param {string}   [options.protocol='tcp'] The protocol of the relational database.
   * @param {object}   [options.define={}] Default options for model definitions. See {@link Model.init}.
   * @param {object}   [options.query={}] Default options for sequelize.query
   * @param {string}   [options.schema=null] A schema to use
   * @param {object}   [options.set={}] Default options for sequelize.set
   * @param {object}   [options.sync={}] Default options for sequelize.sync
   * @param {string}   [options.timezone='+00:00'] The timezone used when converting a date from the database into a JavaScript date. The timezone is also used to SET TIMEZONE when connecting to the server, to ensure that the result of NOW, CURRENT_TIMESTAMP and other time related functions have in the right timezone. For best cross platform performance use the format +/-HH:MM. Will also accept string versions of timezones used by moment.js (e.g. 'America/Los_Angeles'); this is useful to capture daylight savings time changes.
   * @param {string|boolean} [options.clientMinMessages='warning'] The PostgreSQL `client_min_messages` session parameter. Set to `false` to not override the database's default.
   * @param {boolean}  [options.standardConformingStrings=true] The PostgreSQL `standard_conforming_strings` session parameter. Set to `false` to not set the option. WARNING: Setting this to false may expose vulnerabilities and is not recommended!
   * @param {Function} [options.logging=console.log] A function that gets executed every time Sequelize would log something. Function may receive multiple parameters but only first one is printed by `console.log`. To print all values use `(...msg) => console.log(msg)`
   * @param {boolean}  [options.benchmark=false] Pass query execution time in milliseconds as second argument to logging function (options.logging).
   * @param {boolean}  [options.omitNull=false] A flag that defines if null values should be passed as values to CREATE/UPDATE SQL queries or not.
   * @param {boolean}  [options.native=false] A flag that defines if native library shall be used or not. Currently only has an effect for postgres
   * @param {boolean}  [options.replication=false] Use read / write replication. To enable replication, pass an object, with two properties, read and write. Write should be an object (a single server for handling writes), and read an array of object (several servers to handle reads). Each read/write server can have the following properties: `host`, `port`, `username`, `password`, `database`
   * @param {object}   [options.pool] sequelize connection pool configuration
   * @param {number}   [options.pool.max=5] Maximum number of connection in pool
   * @param {number}   [options.pool.min=0] Minimum number of connection in pool
   * @param {number}   [options.pool.idle=10000] The maximum time, in milliseconds, that a connection can be idle before being released.
   * @param {number}   [options.pool.acquire=60000] The maximum time, in milliseconds, that pool will try to get connection before throwing error
   * @param {number}   [options.pool.evict=1000] The time interval, in milliseconds, after which sequelize-pool will remove idle connections.
   * @param {Function} [options.pool.validate] A function that validates a connection. Called with client. The default function checks that client is an object, and that its state is not disconnected
   * @param {number}   [options.pool.maxUses=Infinity] The number of times a connection can be used before discarding it for a replacement, [`used for eventual cluster rebalancing`](https://github.com/sequelize/sequelize-pool).
   * @param {boolean}  [options.quoteIdentifiers=true] Set to `false` to make table names and attributes case-insensitive on Postgres and skip double quoting of them.  WARNING: Setting this to false may expose vulnerabilities and is not recommended!
   * @param {string}   [options.transactionType='DEFERRED'] Set the default transaction type. See `Sequelize.Transaction.TYPES` for possible options. Sqlite only.
   * @param {string}   [options.isolationLevel] Set the default transaction isolation level. See `Sequelize.Transaction.ISOLATION_LEVELS` for possible options.
   * @param {object}   [options.retry] Set of flags that control when a query is automatically retried. Accepts all options for [`retry-as-promised`](https://github.com/mickhansen/retry-as-promised).
   * @param {Array}    [options.retry.match] Only retry a query if the error matches one of these strings.
   * @param {number}   [options.retry.max] How many times a failing query is automatically retried.  Set to 0 to disable retrying on SQL_BUSY error.
   * @param {boolean}  [options.typeValidation=false] Run built-in type validators on insert and update, and select with where clause, e.g. validate that arguments passed to integer fields are integer-like.
   * @param {object}   [options.operatorsAliases] String based operator alias. Pass object to limit set of aliased operators.
   * @param {object}   [options.hooks] An object of global hook functions that are called before and after certain lifecycle events. Global hooks will run after any model-specific hooks defined for the same event (See `Sequelize.Model.init()` for a list).  Additionally, `beforeConnect()`, `afterConnect()`, `beforeDisconnect()`, and `afterDisconnect()` hooks may be defined here.
   * @param {boolean}  [options.minifyAliases=false] A flag that defines if aliases should be minified (mostly useful to avoid Postgres alias character limit of 64)
   * @param {boolean}  [options.logQueryParameters=false] A flag that defines if show bind patameters in log.
   */
  constructor(database, username, password, options) {
    let config;

    if (arguments.length === 1 && typeof database === 'object') {
      // new Sequelize({ ... options })
      options = database;
      config = _.pick(options, 'host', 'port', 'database', 'username', 'password');
    } else if (arguments.length === 1 && typeof database === 'string' || arguments.length === 2 && typeof username === 'object') {
      // new Sequelize(URI, { ... options })

      config = {};
      options = username || {};

      const urlParts = url.parse(arguments[0], true);

      options.dialect = urlParts.protocol.replace(/:$/, '');
      options.host = urlParts.hostname;

      if (options.dialect === 'sqlite' && urlParts.pathname && !urlParts.pathname.startsWith('/:memory')) {
        const storagePath = path.join(options.host, urlParts.pathname);
        options.storage = path.resolve(options.storage || storagePath);
      }

      if (urlParts.pathname) {
        config.database = urlParts.pathname.replace(/^\//, '');
      }

      if (urlParts.port) {
        options.port = urlParts.port;
      }

      if (urlParts.auth) {
        const authParts = urlParts.auth.split(':');

        config.username = authParts[0];

        if (authParts.length > 1)
          config.password = authParts.slice(1).join(':');
      }

      if (urlParts.query) {
        // Allow host query argument to override the url host.
        // Enables specifying domain socket hosts which cannot be specified via the typical
        // host part of a url.
        if (urlParts.query.host) {
          options.host = urlParts.query.host;
        }

        if (options.dialectOptions) {
          Object.assign(options.dialectOptions, urlParts.query);
        } else {
          options.dialectOptions = urlParts.query;
          if (urlParts.query.options) {
            try {
              const o = JSON.parse(urlParts.query.options);
              options.dialectOptions.options = o;
            } catch (e) {
              // Nothing to do, string is not a valid JSON
              // an thus does not need any further processing
            }
          }
        }
      }
    } else {
      // new Sequelize(database, username, password, { ... options })
      options = options || {};
      config = { database, username, password };
    }

    Sequelize.runHooks('beforeInit', config, options);

    this.options = {
      dialect: null,
      dialectModule: null,
      dialectModulePath: null,
      host: 'localhost',
      protocol: 'tcp',
      define: {},
      query: {},
      sync: {},
      timezone: '+00:00',
      clientMinMessages: 'warning',
      standardConformingStrings: true,
      // eslint-disable-next-line no-console
      logging: console.log,
      omitNull: false,
      native: false,
      replication: false,
      ssl: undefined,
      pool: {},
      quoteIdentifiers: true,
      hooks: {},
      retry: {
        max: 5,
        match: [
          'SQLITE_BUSY: database is locked'
        ]
      },
      transactionType: Transaction.TYPES.DEFERRED,
      isolationLevel: null,
      databaseVersion: 0,
      typeValidation: false,
      benchmark: false,
      minifyAliases: false,
      logQueryParameters: false,
      ...options
    };

    if (!this.options.dialect) {
      throw new Error('Dialect needs to be explicitly supplied as of v4.0.0');
    }

    if (this.options.dialect === 'postgresql') {
      this.options.dialect = 'postgres';
    }

    if (this.options.dialect === 'sqlite' && this.options.timezone !== '+00:00') {
      throw new Error('Setting a custom timezone is not supported by SQLite, dates are always returned as UTC. Please remove the custom timezone parameter.');
    }

    if (this.options.logging === true) {
      deprecations.noTrueLogging();
      // eslint-disable-next-line no-console
      this.options.logging = console.log;
    }

    this._setupHooks(options.hooks);

    this.config = {
      database: config.database || this.options.database,
      username: config.username || this.options.username,
      password: config.password || this.options.password || null,
      host: config.host || this.options.host,
      port: config.port || this.options.port,
      pool: this.options.pool,
      protocol: this.options.protocol,
      native: this.options.native,
      ssl: this.options.ssl,
      replication: this.options.replication,
      dialectModule: this.options.dialectModule,
      dialectModulePath: this.options.dialectModulePath,
      keepDefaultTimezone: this.options.keepDefaultTimezone,
      dialectOptions: this.options.dialectOptions
    };

    let Dialect;
    // Requiring the dialect in a switch-case to keep the
    // require calls static. (Browserify fix)
    switch (this.getDialect()) {
      case 'mariadb':
        Dialect = require('./dialects/mariadb');
        break;
      case 'mssql':
        Dialect = require('./dialects/mssql');
        break;
      case 'mysql':
        Dialect = require('./dialects/mysql');
        break;
      case 'postgres':
        Dialect = require('./dialects/postgres');
        break;
      case 'sqlite':
        Dialect = require('./dialects/sqlite');
        break;
      default:
        throw new Error(`The dialect ${this.getDialect()} is not supported. Supported dialects: mssql, mariadb, mysql, postgres, and sqlite.`);
    }

    this.dialect = new Dialect(this);
    this.dialect.queryGenerator.typeValidation = options.typeValidation;

    if (_.isPlainObject(this.options.operatorsAliases)) {
      deprecations.noStringOperators();
      this.dialect.queryGenerator.setOperatorsAliases(this.options.operatorsAliases);
    } else if (typeof this.options.operatorsAliases === 'boolean') {
      deprecations.noBoolOperatorAliases();
    }

    this.queryInterface = this.dialect.queryInterface;

    /**
     * Models are stored here under the name given to `sequelize.define`
     */
    this.models = {};
    this.modelManager = new ModelManager(this);
    this.connectionManager = this.dialect.connectionManager;

    Sequelize.runHooks('afterInit', this);
  }

  /**
   * Refresh data types and parsers.
   *
   * @private
   */
  refreshTypes() {
    this.connectionManager.refreshTypeParser(DataTypes);
  }

  /**
   * Returns the specified dialect.
   *
   * @returns {string} The specified dialect.
   */
  getDialect() {
    return this.options.dialect;
  }

  /**
   * Returns the database name.
   *
   * @returns {string} The database name.
   */
  getDatabaseName() {
    return this.config.database;
  }

  /**
   * Returns an instance of QueryInterface.
   *
   * @returns {QueryInterface} An instance (singleton) of QueryInterface.
   */
  getQueryInterface() {
    return this.queryInterface;
  }

  /**
   * Define a new model, representing a table in the database.
   *
   * The table columns are defined by the object that is given as the second argument. Each key of the object represents a column
   *
   * @param {string} modelName The name of the model. The model will be stored in `sequelize.models` under this name
   * @param {object} attributes An object, where each attribute is a column of the table. See {@link Model.init}
   * @param {object} [options] These options are merged with the default define options provided to the Sequelize constructor and passed to Model.init()
   *
   * @see
   * {@link Model.init} for a more comprehensive specification of the `options` and `attributes` objects.
   * @see
   * <a href="/master/manual/model-basics.html">Model Basics</a> guide
   *
   * @returns {Model} Newly defined model
   *
   * @example
   * sequelize.define('modelName', {
   *   columnA: {
   *       type: Sequelize.BOOLEAN,
   *       validate: {
   *         is: ["[a-z]",'i'],        // will only allow letters
   *         max: 23,                  // only allow values <= 23
   *         isIn: {
   *           args: [['en', 'zh']],
   *           msg: "Must be English or Chinese"
   *         }
   *       },
   *       field: 'column_a'
   *   },
   *   columnB: Sequelize.STRING,
   *   columnC: 'MY VERY OWN COLUMN TYPE'
   * });
   *
   * sequelize.models.modelName // The model will now be available in models under the name given to define
   */
  define(modelName, attributes, options = {}) {
    options.modelName = modelName;
    options.sequelize = this;

    const model = class extends Model {};

    model.init(attributes, options);

    return model;
  }

  /**
   * Fetch a Model which is already defined
   *
   * @param {string} modelName The name of a model defined with Sequelize.define
   *
   * @throws Will throw an error if the model is not defined (that is, if sequelize#isDefined returns false)
   * @returns {Model} Specified model
   */
  model(modelName) {
    if (!this.isDefined(modelName)) {
      throw new Error(`${modelName} has not been defined`);
    }

    return this.modelManager.getModel(modelName);
  }

  /**
   * Checks whether a model with the given name is defined
   *
   * @param {string} modelName The name of a model defined with Sequelize.define
   *
   * @returns {boolean} Returns true if model is already defined, otherwise false
   */
  isDefined(modelName) {
    return !!this.modelManager.models.find(model => model.name === modelName);
  }

  /**
   * Execute a query on the DB, optionally bypassing all the Sequelize goodness.
   *
   * By default, the function will return two arguments: an array of results, and a metadata object, containing number of affected rows etc.
   *
   * If you are running a type of query where you don't need the metadata, for example a `SELECT` query, you can pass in a query type to make sequelize format the results:
   *
   * ```js
   * const [results, metadata] = await sequelize.query('SELECT...'); // Raw query - use array destructuring
   *
   * const results = await sequelize.query('SELECT...', { type: sequelize.QueryTypes.SELECT }); // SELECT query - no destructuring
   * ```
   *
   * @param {string}          sql
   * @param {object}          [options={}] Query options.
   * @param {boolean}         [options.raw] If true, sequelize will not try to format the results of the query, or build an instance of a model from the result
   * @param {Transaction}     [options.transaction=null] The transaction that the query should be executed under
   * @param {QueryTypes}      [options.type='RAW'] The type of query you are executing. The query type affects how results are formatted before they are passed back. The type is a string, but `Sequelize.QueryTypes` is provided as convenience shortcuts.
   * @param {boolean}         [options.nest=false] If true, transforms objects with `.` separated property names into nested objects using [dottie.js](https://github.com/mickhansen/dottie.js). For example { 'user.username': 'john' } becomes { user: { username: 'john' }}. When `nest` is true, the query type is assumed to be `'SELECT'`, unless otherwise specified
   * @param {boolean}         [options.plain=false] Sets the query type to `SELECT` and return a single row
   * @param {object|Array}    [options.replacements] Either an object of named parameter replacements in the format `:param` or an array of unnamed replacements to replace `?` in your SQL.
   * @param {object|Array}    [options.bind] Either an object of named bind parameter in the format `_param` or an array of unnamed bind parameter to replace `$1, $2, ...` in your SQL.
   * @param {boolean}         [options.useMaster=false] Force the query to use the write pool, regardless of the query type.
   * @param {Function}        [options.logging=false] A function that gets executed while running the query to log the sql.
   * @param {Model}           [options.instance] A sequelize model instance whose Model is to be used to build the query result
   * @param {typeof Model}    [options.model] A sequelize model used to build the returned model instances
   * @param {object}          [options.retry] Set of flags that control when a query is automatically retried. Accepts all options for [`retry-as-promised`](https://github.com/mickhansen/retry-as-promised).
   * @param {Array}           [options.retry.match] Only retry a query if the error matches one of these strings.
   * @param {Integer}         [options.retry.max] How many times a failing query is automatically retried.
   * @param {string}          [options.searchPath=DEFAULT] An optional parameter to specify the schema search_path (Postgres only)
   * @param {boolean}         [options.supportsSearchPath] If false do not prepend the query with the search_path (Postgres only)
   * @param {boolean}         [options.mapToModel=false] Map returned fields to model's fields if `options.model` or `options.instance` is present. Mapping will occur before building the model instance.
   * @param {object}          [options.fieldMap] Map returned fields to arbitrary names for `SELECT` query type.
   *
   * @returns {Promise}
   *
   * @see {@link Model.build} for more information about instance option.
   */

  async query(sql, options) {
    options = { ...this.options.query, ...options };

    if (options.instance && !options.model) {
      options.model = options.instance.constructor;
    }

    if (!options.instance && !options.model) {
      options.raw = true;
    }

    // map raw fields to model attributes
    if (options.mapToModel) {
      options.fieldMap = _.get(options, 'model.fieldAttributeMap', {});
    }

    options = _.defaults(options, {
      // eslint-disable-next-line no-console
      logging: Object.prototype.hasOwnProperty.call(this.options, 'logging') ? this.options.logging : console.log,
      searchPath: Object.prototype.hasOwnProperty.call(this.options, 'searchPath') ? this.options.searchPath : 'DEFAULT'
    });

    if (!options.type) {
      if (options.model || options.nest || options.plain) {
        options.type = QueryTypes.SELECT;
      } else {
        options.type = QueryTypes.RAW;
      }
    }

    //if dialect doesn't support search_path or dialect option
    //to prepend searchPath is not true delete the searchPath option
    if (
      !this.dialect.supports.searchPath ||
      !this.options.dialectOptions ||
      !this.options.dialectOptions.prependSearchPath ||
      options.supportsSearchPath === false
    ) {
      delete options.searchPath;
    } else if (!options.searchPath) {
      //if user wants to always prepend searchPath (dialectOptions.preprendSearchPath = true)
      //then set to DEFAULT if none is provided
      options.searchPath = 'DEFAULT';
    }

    if (typeof sql === 'object') {
      if (sql.values !== undefined) {
        if (options.replacements !== undefined) {
          throw new Error('Both `sql.values` and `options.replacements` cannot be set at the same time');
        }
        options.replacements = sql.values;
      }

      if (sql.bind !== undefined) {
        if (options.bind !== undefined) {
          throw new Error('Both `sql.bind` and `options.bind` cannot be set at the same time');
        }
        options.bind = sql.bind;
      }

      if (sql.query !== undefined) {
        sql = sql.query;
      }
    }

    sql = sql.trim();

    if (options.replacements && options.bind) {
      throw new Error('Both `replacements` and `bind` cannot be set at the same time');
    }

    if (options.replacements) {
      if (Array.isArray(options.replacements)) {
        sql = Utils.format([sql].concat(options.replacements), this.options.dialect);
      } else {
        sql = Utils.formatNamedParameters(sql, options.replacements, this.options.dialect);
      }
    }

    let bindParameters;

    if (options.bind) {
      [sql, bindParameters] = this.dialect.Query.formatBindParameters(sql, options.bind, this.options.dialect);
    }

    const checkTransaction = () => {
      if (options.transaction && options.transaction.finished && !options.completesTransaction) {
        const error = new Error(`${options.transaction.finished} has been called on this transaction(${options.transaction.id}), you can no longer use it. (The rejected query is attached as the 'sql' property of this error)`);
        error.sql = sql;
        throw error;
      }
    };

    const retryOptions = { ...this.options.retry, ...options.retry };

    return retry(async () => {
      if (options.transaction === undefined && Sequelize._cls) {
        options.transaction = Sequelize._cls.get('transaction');
      }

      checkTransaction();

      const connection = await (options.transaction ? options.transaction.connection : this.connectionManager.getConnection(options));
      const query = new this.dialect.Query(connection, this, options);

      try {
        await this.runHooks('beforeQuery', options, query);
        checkTransaction();
        return await query.run(sql, bindParameters);
      } finally {
        await this.runHooks('afterQuery', options, query);
        if (!options.transaction) {
          await this.connectionManager.releaseConnection(connection);
        }
      }
    }, retryOptions);
  }

  /**
   * Execute a query which would set an environment or user variable. The variables are set per connection, so this function needs a transaction.
   * Only works for MySQL.
   *
   * @param {object}        variables Object with multiple variables.
   * @param {object}        [options] query options.
   * @param {Transaction}   [options.transaction] The transaction that the query should be executed under
   *
   * @memberof Sequelize
   *
   * @returns {Promise}
   */
  async set(variables, options) {

    // Prepare options
    options = { ...this.options.set, ...typeof options === 'object' && options };

    if (this.options.dialect !== 'mysql') {
      throw new Error('sequelize.set is only supported for mysql');
    }
    if (!options.transaction || !(options.transaction instanceof Transaction) ) {
      throw new TypeError('options.transaction is required');
    }

    // Override some options, since this isn't a SELECT
    options.raw = true;
    options.plain = true;
    options.type = 'SET';

    // Generate SQL Query
    const query =
      `SET ${
        _.map(variables, (v, k) => `@${k} := ${typeof v === 'string' ? `"${v}"` : v}`).join(', ')}`;

    return await this.query(query, options);
  }

  /**
   * Escape value.
   *
   * @param {string} value string value to escape
   *
   * @returns {string}
   */
  escape(value) {
    return this.dialect.queryGenerator.escape(value);
  }

  /**
   * Create a new database schema.
   *
   * **Note:** this is a schema in the [postgres sense of the word](http://www.postgresql.org/docs/9.1/static/ddl-schemas.html),
   * not a database table. In mysql and sqlite, this command will do nothing.
   *
   * @see
   * {@link Model.schema}
   *
   * @param {string} schema Name of the schema
   * @param {object} [options={}] query options
   * @param {boolean|Function} [options.logging] A function that logs sql queries, or false for no logging
   *
   * @returns {Promise}
   */
  async createSchema(schema, options) {
    return await this.getQueryInterface().createSchema(schema, options);
  }

  /**
   * Show all defined schemas
   *
   * **Note:** this is a schema in the [postgres sense of the word](http://www.postgresql.org/docs/9.1/static/ddl-schemas.html),
   * not a database table. In mysql and sqlite, this will show all tables.
   *
   * @param {object} [options={}] query options
   * @param {boolean|Function} [options.logging] A function that logs sql queries, or false for no logging
   *
   * @returns {Promise}
   */
  async showAllSchemas(options) {
    return await this.getQueryInterface().showAllSchemas(options);
  }

  /**
   * Drop a single schema
   *
   * **Note:** this is a schema in the [postgres sense of the word](http://www.postgresql.org/docs/9.1/static/ddl-schemas.html),
   * not a database table. In mysql and sqlite, this drop a table matching the schema name
   *
   * @param {string} schema Name of the schema
   * @param {object} [options={}] query options
   * @param {boolean|Function} [options.logging] A function that logs sql queries, or false for no logging
   *
   * @returns {Promise}
   */
  async dropSchema(schema, options) {
    return await this.getQueryInterface().dropSchema(schema, options);
  }

  /**
   * Drop all schemas.
   *
   * **Note:** this is a schema in the [postgres sense of the word](http://www.postgresql.org/docs/9.1/static/ddl-schemas.html),
   * not a database table. In mysql and sqlite, this is the equivalent of drop all tables.
   *
   * @param {object} [options={}] query options
   * @param {boolean|Function} [options.logging] A function that logs sql queries, or false for no logging
   *
   * @returns {Promise}
   */
  async dropAllSchemas(options) {
    return await this.getQueryInterface().dropAllSchemas(options);
  }

  /**
   * Sync all defined models to the DB.
   *
   * @param {object} [options={}] sync options
   * @param {boolean} [options.force=false] If force is true, each Model will run `DROP TABLE IF EXISTS`, before it tries to create its own table
   * @param {RegExp} [options.match] Match a regex against the database name before syncing, a safety check for cases where force: true is used in tests but not live code
   * @param {boolean|Function} [options.logging=console.log] A function that logs sql queries, or false for no logging
   * @param {string} [options.schema='public'] The schema that the tables should be created in. This can be overridden for each table in sequelize.define
   * @param {string} [options.searchPath=DEFAULT] An optional parameter to specify the schema search_path (Postgres only)
   * @param {boolean} [options.hooks=true] If hooks is true then beforeSync, afterSync, beforeBulkSync, afterBulkSync hooks will be called
   * @param {boolean|object} [options.alter=false] Alters tables to fit models. Provide an object for additional configuration. Not recommended for production use. If not further configured deletes data in columns that were removed or had their type changed in the model.
   * @param {boolean} [options.alter.drop=true] Prevents any drop statements while altering a table when set to `false`
   *
   * @returns {Promise}
   */
  async sync(options) {
    options = {
      ...this.options,
      ...this.options.sync,
      ...options,
      hooks: options ? options.hooks !== false : true
    };

    if (options.match) {
      if (!options.match.test(this.config.database)) {
        throw new Error(`Database "${this.config.database}" does not match sync match parameter "${options.match}"`);
      }
    }

    if (options.hooks) {
      await this.runHooks('beforeBulkSync', options);
    }
    if (options.force) {
      await this.drop(options);
    }
    const models = [];

    // Topologically sort by foreign key constraints to give us an appropriate
    // creation order
    this.modelManager.forEachModel(model => {
      if (model) {
        models.push(model);
      } else {
        // DB should throw an SQL error if referencing non-existent table
      }
    });

    // no models defined, just authenticate
    if (!models.length) {
      await this.authenticate(options);
    } else {
      for (const model of models) await model.sync(options);
    }
    if (options.hooks) {
      await this.runHooks('afterBulkSync', options);
    }
    return this;
  }

  /**
   * Truncate all tables defined through the sequelize models.
   * This is done by calling `Model.truncate()` on each model.
   *
   * @param {object} [options] The options passed to Model.destroy in addition to truncate
   * @param {boolean|Function} [options.logging] A function that logs sql queries, or false for no logging
   * @returns {Promise}
   *
   * @see
   * {@link Model.truncate} for more information
   */
  async truncate(options) {
    const models = [];

    this.modelManager.forEachModel(model => {
      if (model) {
        models.push(model);
      }
    }, { reverse: false });

    if (options && options.cascade) {
      for (const model of models) await model.truncate(options);
    } else {
      await Promise.all(models.map(model => model.truncate(options)));
    }
  }

  /**
   * Drop all tables defined through this sequelize instance.
   * This is done by calling Model.drop on each model.
   *
   * @see
   * {@link Model.drop} for options
   *
   * @param {object} [options] The options passed to each call to Model.drop
   * @param {boolean|Function} [options.logging] A function that logs sql queries, or false for no logging
   *
   * @returns {Promise}
   */
  async drop(options) {
    const models = [];

    this.modelManager.forEachModel(model => {
      if (model) {
        models.push(model);
      }
    }, { reverse: false });

    for (const model of models) await model.drop(options);
  }

  /**
   * Test the connection by trying to authenticate. It runs `SELECT 1+1 AS result` query.
   *
   * @param {object} [options={}] query options
   *
   * @returns {Promise}
   */
  async authenticate(options) {
    options = {
      raw: true,
      plain: true,
      type: QueryTypes.SELECT,
      ...options
    };

    await this.query('SELECT 1+1 AS result', options);

    return;
  }

  async databaseVersion(options) {
    return await this.getQueryInterface().databaseVersion(options);
  }

  /**
   * Get the fn for random based on the dialect
   *
   * @returns {Sequelize.fn}
   */
  random() {
    const dia = this.getDialect();
    if (dia === 'postgres' || dia === 'sqlite') {
      return this.fn('RANDOM');
    }
    return this.fn('RAND');
  }

  /**
   * Creates an object representing a database function. This can be used in search queries, both in where and order parts, and as default values in column definitions.
   * If you want to refer to columns in your function, you should use `sequelize.col`, so that the columns are properly interpreted as columns and not a strings.
   *
   * @see
   * {@link Model.findAll}
   * @see
   * {@link Sequelize.define}
   * @see
   * {@link Sequelize.col}
   *
   * @param {string} fn The function you want to call
   * @param {any} args All further arguments will be passed as arguments to the function
   *
   * @since v2.0.0-dev3
   * @memberof Sequelize
   * @returns {Sequelize.fn}
   *
   * @example <caption>Convert a user's username to upper case</caption>
   * instance.update({
   *   username: sequelize.fn('upper', sequelize.col('username'))
   * });
   */
  static fn(fn, ...args) {
    return new Utils.Fn(fn, args);
  }

  /**
   * Creates an object which represents a column in the DB, this allows referencing another column in your query. This is often useful in conjunction with `sequelize.fn`, since raw string arguments to fn will be escaped.
   *
   * @see
   * {@link Sequelize#fn}
   *
   * @param {string} col The name of the column
   * @since v2.0.0-dev3
   * @memberof Sequelize
   *
   * @returns {Sequelize.col}
   */
  static col(col) {
    return new Utils.Col(col);
  }

  /**
   * Creates an object representing a call to the cast function.
   *
   * @param {any} val The value to cast
   * @param {string} type The type to cast it to
   * @since v2.0.0-dev3
   * @memberof Sequelize
   *
   * @returns {Sequelize.cast}
   */
  static cast(val, type) {
    return new Utils.Cast(val, type);
  }

  /**
   * Creates an object representing a literal, i.e. something that will not be escaped.
   *
   * @param {any} val literal value
   * @since v2.0.0-dev3
   * @memberof Sequelize
   *
   * @returns {Sequelize.literal}
   */
  static literal(val) {
    return new Utils.Literal(val);
  }

  /**
   * An AND query
   *
   * @see
   * {@link Model.findAll}
   *
   * @param {...string|object} args Each argument will be joined by AND
   * @since v2.0.0-dev3
   * @memberof Sequelize
   *
   * @returns {Sequelize.and}
   */
  static and(...args) {
    return { [Op.and]: args };
  }

  /**
   * An OR query
   *
   * @see
   * {@link Model.findAll}
   *
   * @param {...string|object} args Each argument will be joined by OR
   * @since v2.0.0-dev3
   * @memberof Sequelize
   *
   * @returns {Sequelize.or}
   */
  static or(...args) {
    return { [Op.or]: args };
  }

  /**
   * Creates an object representing nested where conditions for postgres/sqlite/mysql json data-type.
   *
   * @see
   * {@link Model.findAll}
   *
   * @param {string|object} conditionsOrPath A hash containing strings/numbers or other nested hash, a string using dot notation or a string using postgres/sqlite/mysql json syntax.
   * @param {string|number|boolean} [value] An optional value to compare against. Produces a string of the form "<json path> = '<value>'".
   * @memberof Sequelize
   *
   * @returns {Sequelize.json}
   */
  static json(conditionsOrPath, value) {
    return new Utils.Json(conditionsOrPath, value);
  }

  /**
   * A way of specifying attr = condition.
   *
   * The attr can either be an object taken from `Model.rawAttributes` (for example `Model.rawAttributes.id` or `Model.rawAttributes.name`). The
   * attribute should be defined in your model definition. The attribute can also be an object from one of the sequelize utility functions (`sequelize.fn`, `sequelize.col` etc.)
   *
   * For string attributes, use the regular `{ where: { attr: something }}` syntax. If you don't want your string to be escaped, use `sequelize.literal`.
   *
   * @see
   * {@link Model.findAll}
   *
   * @param {object} attr The attribute, which can be either an attribute object from `Model.rawAttributes` or a sequelize object, for example an instance of `sequelize.fn`. For simple string attributes, use the POJO syntax
   * @param {symbol} [comparator='Op.eq'] operator
   * @param {string|object} logic The condition. Can be both a simply type, or a further condition (`or`, `and`, `.literal` etc.)
   * @since v2.0.0-dev3
   */
  static where(attr, comparator, logic) {
    return new Utils.Where(attr, comparator, logic);
  }

  /**
   * Start a transaction. When using transactions, you should pass the transaction in the options argument in order for the query to happen under that transaction @see {@link Transaction}
   *
   * If you have [CLS](https://github.com/Jeff-Lewis/cls-hooked) enabled, the transaction will automatically be passed to any query that runs within the callback
   *
   * @example
   *
   * try {
   *   const transaction = await sequelize.transaction();
   *   const user = await User.findOne(..., { transaction });
   *   await user.update(..., { transaction });
   *   await transaction.commit();
   * } catch {
   *   await transaction.rollback()
   * }
   *
   * @example <caption>A syntax for automatically committing or rolling back based on the promise chain resolution is also supported</caption>
   *
   * try {
   *   await sequelize.transaction(transaction => { // Note that we pass a callback rather than awaiting the call with no arguments
   *     const user = await User.findOne(..., {transaction});
   *     await user.update(..., {transaction});
   *   });
   *   // Committed
   * } catch(err) {
   *   // Rolled back
   *   console.error(err);
   * }
   * @example <caption>To enable CLS, add it do your project, create a namespace and set it on the sequelize constructor:</caption>
   *
   * const cls = require('cls-hooked');
   * const namespace = cls.createNamespace('....');
   * const Sequelize = require('sequelize');
   * Sequelize.useCLS(namespace);
   *
   * // Note, that CLS is enabled for all sequelize instances, and all instances will share the same namespace
   *
   * @param {object}   [options] Transaction options
   * @param {string}   [options.type='DEFERRED'] See `Sequelize.Transaction.TYPES` for possible options. Sqlite only.
   * @param {string}   [options.isolationLevel] See `Sequelize.Transaction.ISOLATION_LEVELS` for possible options
   * @param {string}   [options.deferrable] Sets the constraints to be deferred or immediately checked. See `Sequelize.Deferrable`. PostgreSQL Only
   * @param {Function} [options.logging=false] A function that gets executed while running the query to log the sql.
   * @param {Function} [autoCallback] The callback is called with the transaction object, and should return a promise. If the promise is resolved, the transaction commits; if the promise rejects, the transaction rolls back
   *
   * @returns {Promise}
   */
  async transaction(options, autoCallback) {
    if (typeof options === 'function') {
      autoCallback = options;
      options = undefined;
    }

    const transaction = new Transaction(this, options);

    if (!autoCallback) {
      await transaction.prepareEnvironment(false);
      return transaction;
    }

    // autoCallback provided
    return Sequelize._clsRun(async () => {
      try {
        await transaction.prepareEnvironment();
        const result = await autoCallback(transaction);
        await transaction.commit();
        return await result;
      } catch (err) {
        if (!transaction.finished) {
          try {
            await transaction.rollback();
          } catch (err0) {
            // ignore
          }
        }
        throw err;
      }
    });
  }

  /**
   * Use CLS with Sequelize.
   * CLS namespace provided is stored as `Sequelize._cls`
   *
   * @param {object} ns CLS namespace
   * @returns {object} Sequelize constructor
   */
  static useCLS(ns) {
    // check `ns` is valid CLS namespace
    if (!ns || typeof ns !== 'object' || typeof ns.bind !== 'function' || typeof ns.run !== 'function') throw new Error('Must provide CLS namespace');

    // save namespace as `Sequelize._cls`
    this._cls = ns;

    // return Sequelize for chaining
    return this;
  }

  /**
   * Run function in CLS context.
   * If no CLS context in use, just runs the function normally
   *
   * @private
   * @param {Function} fn Function to run
   * @returns {*} Return value of function
   */
  static _clsRun(fn) {
    const ns = Sequelize._cls;
    if (!ns) return fn();

    let res;
    ns.run(context => res = fn(context));
    return res;
  }

  log(...args) {
    let options;

    const last = _.last(args);

    if (last && _.isPlainObject(last) && Object.prototype.hasOwnProperty.call(last, 'logging')) {
      options = last;

      // remove options from set of logged arguments if options.logging is equal to console.log
      // eslint-disable-next-line no-console
      if (options.logging === console.log) {
        args.splice(args.length - 1, 1);
      }
    } else {
      options = this.options;
    }

    if (options.logging) {
      if (options.logging === true) {
        deprecations.noTrueLogging();
        // eslint-disable-next-line no-console
        options.logging = console.log;
      }

      // second argument is sql-timings, when benchmarking option enabled
      // eslint-disable-next-line no-console
      if ((this.options.benchmark || options.benchmark) && options.logging === console.log) {
        args = [`${args[0]} Elapsed time: ${args[1]}ms`];
      }

      options.logging(...args);
    }
  }

  /**
   * Close all connections used by this sequelize instance, and free all references so the instance can be garbage collected.
   *
   * Normally this is done on process exit, so you only need to call this method if you are creating multiple instances, and want
   * to garbage collect some of them.
   *
   * @returns {Promise}
   */
  close() {
    return this.connectionManager.close();
  }

  normalizeDataType(Type) {
    let type = typeof Type === 'function' ? new Type() : Type;
    const dialectTypes = this.dialect.DataTypes || {};

    if (dialectTypes[type.key]) {
      type = dialectTypes[type.key].extend(type);
    }

    if (type instanceof DataTypes.ARRAY) {
      if (!type.type) {
        throw new Error('ARRAY is missing type definition for its values.');
      }
      if (dialectTypes[type.type.key]) {
        type.type = dialectTypes[type.type.key].extend(type.type);
      }
    }

    return type;
  }

  normalizeAttribute(attribute) {
    if (!_.isPlainObject(attribute)) {
      attribute = { type: attribute };
    }

    if (!attribute.type) return attribute;

    attribute.type = this.normalizeDataType(attribute.type);

    if (Object.prototype.hasOwnProperty.call(attribute, 'defaultValue')) {
      if (typeof attribute.defaultValue === 'function' && (
        attribute.defaultValue === DataTypes.NOW ||
          attribute.defaultValue === DataTypes.UUIDV1 ||
          attribute.defaultValue === DataTypes.UUIDV4
      )) {
        attribute.defaultValue = new attribute.defaultValue();
      }
    }

    if (attribute.type instanceof DataTypes.ENUM) {
      // The ENUM is a special case where the type is an object containing the values
      if (attribute.values) {
        attribute.type.values = attribute.type.options.values = attribute.values;
      } else {
        attribute.values = attribute.type.values;
      }

      if (!attribute.values.length) {
        throw new Error('Values for ENUM have not been defined.');
      }
    }

    return attribute;
  }
}

// Aliases
Sequelize.prototype.fn = Sequelize.fn;
Sequelize.prototype.col = Sequelize.col;
Sequelize.prototype.cast = Sequelize.cast;
Sequelize.prototype.literal = Sequelize.literal;
Sequelize.prototype.and = Sequelize.and;
Sequelize.prototype.or = Sequelize.or;
Sequelize.prototype.json = Sequelize.json;
Sequelize.prototype.where = Sequelize.where;
Sequelize.prototype.validate = Sequelize.prototype.authenticate;

/**
 * Sequelize version number.
 */
Sequelize.version = require('../package.json').version;

Sequelize.options = { hooks: {} };

/**
 * @private
 */
Sequelize.Utils = Utils;

/**
 * Operators symbols to be used for querying data
 *
 * @see  {@link Operators}
 */
Sequelize.Op = Op;

/**
 * Available table hints to be used for querying data in mssql for table hints
 *
 * @see {@link TableHints}
 */
Sequelize.TableHints = TableHints;

/**
 * Available index hints to be used for querying data in mysql for index hints
 *
 * @see {@link IndexHints}
 */
Sequelize.IndexHints = IndexHints;

/**
 * A reference to the sequelize transaction class. Use this to access isolationLevels and types when creating a transaction
 *
 * @see {@link Transaction}
 * @see {@link Sequelize.transaction}
 */
Sequelize.Transaction = Transaction;

/**
 * A reference to Sequelize constructor from sequelize. Useful for accessing DataTypes, Errors etc.
 *
 * @see {@link Sequelize}
 */
Sequelize.prototype.Sequelize = Sequelize;

/**
 * Available query types for use with `sequelize.query`
 *
 * @see {@link QueryTypes}
 */
Sequelize.prototype.QueryTypes = Sequelize.QueryTypes = QueryTypes;

/**
 * Exposes the validator.js object, so you can extend it with custom validation functions. The validator is exposed both on the instance, and on the constructor.
 *
 * @see https://github.com/chriso/validator.js
 */
Sequelize.prototype.Validator = Sequelize.Validator = Validator;

Sequelize.Model = Model;

Sequelize.DataTypes = DataTypes;
for (const dataType in DataTypes) {
  Sequelize[dataType] = DataTypes[dataType];
}

/**
 * A reference to the deferrable collection. Use this to access the different deferrable options.
 *
 * @see {@link Transaction.Deferrable}
 * @see {@link Sequelize#transaction}
 */
Sequelize.Deferrable = Deferrable;

/**
 * A reference to the sequelize association class.
 *
 * @see {@link Association}
 */
Sequelize.prototype.Association = Sequelize.Association = Association;

/**
 * Provide alternative version of `inflection` module to be used by `Utils.pluralize` etc.
 *
 * @param {object} _inflection - `inflection` module
 */
Sequelize.useInflection = Utils.useInflection;

/**
 * Allow hooks to be defined on Sequelize + on sequelize instance as universal hooks to run on all models
 * and on Sequelize/sequelize methods e.g. Sequelize(), Sequelize#define()
 */
Hooks.applyTo(Sequelize);
Hooks.applyTo(Sequelize.prototype);

/**
 * Expose various errors available
 */

// expose alias to BaseError
Sequelize.Error = sequelizeErrors.BaseError;

for (const error of Object.keys(sequelizeErrors)) {
  Sequelize[error] = sequelizeErrors[error];
}

module.exports = Sequelize;
module.exports.Sequelize = Sequelize;
module.exports.default = Sequelize;