Best way to enable support for old MSSQL

I have been using sequelize with mssql 2012 and things work just fine. However, I need to enable temporary support for using mssql 2005.

I have found 2 issues when using sequelize with mssql 2005:

1. Datetime datatype toSql returns DATETIME2, which doesn’t seem to be supported in mssql 2005. If changed to DATETIME, it works.
2. Inserts on tables fail because createdAt and UpdatedAt are inserted with wrong format for mssql 2005 DATETIME.

I have found where to fix the datatype:

/dialects/mssql/data-types.js

DATE.prototype.toSql = function() {
  return 'DATETIME2';
};

Changing DATETIME2 to DATETIME would work for MSSQL 2005. To adjust createdAt and UpdatedAt formats to fit in the DATETIME field, I found some changes on the following file would be required.

/lib/sql-string.js

SqlString.dateToString = function(date, timeZone, dialect) {
  date = moment(date).utcOffset(timeZone);

  if (dialect === 'mysql' || dialect === 'mariadb') {
    return date.format('YYYY-MM-DD HH:mm:ss');
  } else {
    // ZZ here means current timezone, _not_ UTC
    return date.format('YYYY-MM-DD HH:mm:ss.SSS Z');
  }
};

Adding mssql to the first condition fixes the second issue with the dates.

I have been looking on a way to enable this legacy support but not sure how to do it:

1. Changing the DATE prototype and SqlString.dateToString after referencing Sequelize.
2. Try to create a custom dialect. I tried to use options.dialectModulePath but doesn’t seem to work for this purpose.

Is there any particular way to extend sequelize to enable this?

[itsravenous]

I have the same issue and followed (mostly blindly!) the advice above from @janmeier to create a DATE2005 type in a plugin-ish way. It’s working for me so far, although obviously it relies on data-types.js staying in the same place in the Sequelize lib 😃

orm/custom-data-types.js:

var BaseTypes = require('sequelize/lib/data-types'),
    util = require('util');

var DATE2005 = function() {
    if (!(this instanceof DATE2005)) return new DATE2005();
    BaseTypes.DATE.apply(this, arguments);
};
util.inherits(DATE2005, BaseTypes.ABSTRACT);

DATE2005.prototype.toSql = function() {
    return 'DATETIME';
};

module.exports = {
    DATE2005: DATE2005
};

if (!DATE2005.key) DATE2005.key = DATE2005;
if (!DATE2005.extend) {
    DATE2005.extend = function(oldType) {
        return new DATE2005(oldType.options);
    };
}

models/customer.js:

var customDataTypes = require('../orm/data-types');

var Customer = orm.define('tblCustomers', {
    CustomerID: {
        type: Sequelize.INTEGER,
        primaryKey: true,
        autoIncrement: true
    },
    Forename: {
        type: Sequelize.STRING
    },
    Surname: {
        type: Sequelize.STRING
    },
    DOB: {
        type: customDataTypes.DATE2005
    }
});

[mubaidr]

I am having the same issue. Is it possible to enable datetime support for timestamps?

mssql 2012