Map SQL VARCHAR and TEXT to Sequelize STRING and TEXT

SQL String Types in Sequelize

SQL databases offer several string types with different storage characteristics. Sequelize provides matching DataTypes constants for each, and this converter handles all common variants automatically.

VARCHAR to DataTypes.STRING

The most common string type in SQL is VARCHAR(n), which maps to DataTypes.STRING(n) in Sequelize. The length parameter is preserved:

email VARCHAR(255) NOT NULL
-- becomes -->
email: { type: DataTypes.STRING(255), allowNull: false }

If no length is specified (VARCHAR without parentheses), the converter uses DataTypes.STRING which defaults to 255 characters.

CHAR to DataTypes.CHAR

Fixed-length CHAR(n) maps to DataTypes.CHAR(n). This is less common but useful for codes like country codes or currency codes:

country_code CHAR(2) NOT NULL
-- becomes -->
country_code: { type: DataTypes.CHAR(2), allowNull: false }

TEXT to DataTypes.TEXT

For unbounded text, SQL TEXT, LONGTEXT, MEDIUMTEXT, and TINYTEXT all map to DataTypes.TEXT:

bio TEXT
-- becomes -->
bio: { type: DataTypes.TEXT, allowNull: true }

NVARCHAR and NCHAR

Unicode-specific types like NVARCHAR (SQL Server) map to DataTypes.STRING since Sequelize handles Unicode encoding at the connection level rather than the column level.

Practical Considerations

When choosing between STRING and TEXT, remember that STRING (VARCHAR) columns can be indexed efficiently while TEXT columns typically cannot be used in indexes directly. If you need to search or sort on a column, prefer DataTypes.STRING with an explicit length.