Reference table of all supported column types in the go-migration Schema Builder.

Column Types

The Schema Builder provides methods on the *schema.Blueprint for every supported column type. Each method returns a column definition that you can further customize with column modifiers.

Type Reference

Method	Description	Parameters
`bp.ID(name)`	Auto-incrementing unsigned big integer primary key	`name string`
`bp.String(name, length)`	Variable-length string (VARCHAR)	`name string, length int`
`bp.Text(name)`	Unlimited-length text	`name string`
`bp.Integer(name)`	32-bit integer	`name string`
`bp.BigInteger(name)`	64-bit integer	`name string`
`bp.Boolean(name)`	Boolean true/false	`name string`
`bp.Timestamp(name)`	Timestamp with date and time	`name string`
`bp.Date(name)`	Date without time	`name string`
`bp.Decimal(name, precision, scale)`	Fixed-point decimal number	`name string, precision int, scale int`
`bp.Float(name)`	Floating-point number	`name string`
`bp.UUID(name)`	UUID string	`name string`
`bp.JSON(name)`	JSON data	`name string`
`bp.Binary(name)`	Binary/blob data	`name string`
`bp.Enum(name, allowed)`	Enumerated type with allowed values	`name string, allowed []string`
`bp.Char(name, length)`	Fixed-length character string	`name string, length int`
`bp.LongText(name)`	Long text (MySQL: LONGTEXT, others: TEXT)	`name string`
`bp.MediumText(name)`	Medium text (MySQL: MEDIUMTEXT, others: TEXT)	`name string`
`bp.TinyInt(name)`	Tiny integer (MySQL: TINYINT, PG: SMALLINT, SQLite: INTEGER)	`name string`
`bp.SmallInt(name)`	Small integer (MySQL/PG: SMALLINT, SQLite: INTEGER)	`name string`

Usage Examples

Primary Key

bp.ID("id")

ID creates an auto-incrementing unsigned big integer column and sets it as the primary key. This is the recommended way to define primary keys.

Strings

bp.String("name", 255)
bp.String("email", 255).Unique()
bp.String("slug", 100).Unique()

The second argument sets the maximum character length (maps to VARCHAR(n) in SQL).

Text

bp.Text("body")
bp.Text("description").Nullable()

Use Text for long-form content where you don't need a length limit.

Numeric Types

bp.Integer("age")
bp.BigInteger("population").Unsigned()
bp.Decimal("price", 10, 2)
bp.Float("score")

Decimal takes precision (total digits) and scale (digits after the decimal point). For example, Decimal("price", 10, 2) stores values like 12345678.99.

Boolean

bp.Boolean("active").Default(true)
bp.Boolean("verified").Default(false)

Date and Time

bp.Timestamp("created_at").Nullable()
bp.Timestamp("updated_at").Nullable()
bp.Date("date_of_birth").Nullable()

UUID

bp.UUID("uuid").Primary()
bp.UUID("external_id").Unique()

JSON

bp.JSON("metadata").Nullable()
bp.JSON("settings").Default("{}")

JSON column support depends on your database. PostgreSQL has native JSONB support, MySQL uses JSON, and SQLite stores JSON as text. See Database Grammars for type mapping details.

Binary

bp.Binary("avatar")
bp.Binary("file_data").Nullable()

Enum

bp.Enum("status", []string{"draft", "published", "archived"})
bp.Enum("role", []string{"admin", "editor", "viewer"}).Default("viewer")

Enum restricts a column to a fixed set of allowed values. The implementation varies by database:

Enum behavior differs across databases:

PostgreSQL: VARCHAR(255) with a CHECK constraint — CHECK ("status" IN ('draft','published','archived'))
MySQL: Native ENUM('draft','published','archived') type
SQLite: TEXT with a CHECK constraint — CHECK ("status" IN ('draft','published','archived'))

Char

bp.Char("country_code", 2)
bp.Char("currency_code", 3)

Char creates a fixed-length character column (CHAR(n) in SQL). Use this when values always have the same length, like country codes or currency codes.

LongText and MediumText

bp.LongText("full_content")
bp.MediumText("summary").Nullable()

These provide text columns with size hints for MySQL. On MySQL, LongText maps to LONGTEXT and MediumText maps to MEDIUMTEXT. On PostgreSQL and SQLite, both map to TEXT.

TinyInt and SmallInt

bp.TinyInt("priority")
bp.SmallInt("quantity").Default(0)

Use these for columns that store small numeric ranges to save storage space:

Method	MySQL	PostgreSQL	SQLite
`TinyInt`	`TINYINT`	`SMALLINT`	`INTEGER`
`SmallInt`	`SMALLINT`	`SMALLINT`	`INTEGER`

Complete Example

s.Create("products", func(bp *schema.Blueprint) {
    bp.ID("id")
    bp.UUID("sku").Unique()
    bp.String("name", 255)
    bp.Text("description").Nullable()
    bp.LongText("full_details").Nullable()
    bp.MediumText("summary").Nullable()
    bp.Char("currency_code", 3).Default("USD")
    bp.Decimal("price", 10, 2)
    bp.Integer("stock").Default(0).Unsigned()
    bp.SmallInt("min_order_qty").Default(1)
    bp.TinyInt("priority").Default(0)
    bp.Float("weight")
    bp.Boolean("active").Default(true)
    bp.Enum("status", []string{"draft", "published", "archived"}).Default("draft")
    bp.JSON("attributes").Nullable()
    bp.Binary("thumbnail").Nullable()
    bp.Date("release_date").Nullable()
    bp.Timestamp("created_at").Nullable()
    bp.Timestamp("updated_at").Nullable()
})

What's Next?

Column Modifiers — customize columns with Nullable, Default, Unique, and more
Indexes — add indexes for query performance

Column Types

On this page