go-migrationgo-migration
Schema Builder
Documentation

Creating Tables

Learn how to create database tables using the Schema Builder's s.Create() method with Blueprint callbacks.

Creating Tables

The Schema Builder's Create method defines a new table in your database. You pass a table name and a callback that receives a *schema.Blueprint — the fluent API for adding columns, indexes, and constraints.

Basic Usage

go
s.Create("users", func(bp *schema.Blueprint) {
    bp.ID("id")
    bp.String("name", 255)
    bp.Timestamp("created_at").Nullable()
})

The first argument is the table name. The callback receives a Blueprint where you define columns using chainable methods.

Complete Example

Here's a full migration that creates a posts table with multiple column types, modifiers, an index, and a foreign key:

migrations/20240115_create_posts_table.go
package migrations

import (
    "github.com/gopackx/go-migration/schema"
)

type CreatePostsTable struct{}

func (m *CreatePostsTable) Up(s *schema.Builder) {
    s.Create("posts", func(bp *schema.Blueprint) {
        bp.ID("id")
        bp.BigInteger("user_id").Unsigned()
        bp.String("title", 255)
        bp.Text("body")
        bp.String("slug", 255).Unique()
        bp.Boolean("published").Default(false)
        bp.Integer("view_count").Default(0).Unsigned()
        bp.Decimal("rating", 3, 2).Nullable()
        bp.JSON("metadata").Nullable()
        bp.Timestamp("published_at").Nullable()
        bp.Timestamp("created_at").Nullable()
        bp.Timestamp("updated_at").Nullable()

        // Add an index for faster lookups
        bp.Index("idx_posts_user_id", "user_id")

        // Add a foreign key constraint
        bp.Foreign("user_id").References("id").On("users").OnDelete("CASCADE")
    })
}

func (m *CreatePostsTable) Down(s *schema.Builder) {
    s.DropIfExists("posts")
}

How It Works

When you call s.Create():

  1. The Blueprint callback is executed to collect all column definitions, indexes, and constraints
  2. The active database grammar translates the Blueprint into a CREATE TABLE SQL statement
  3. The SQL is executed against the database connection

The Down method should reverse the Up method. For table creation, this typically means calling s.DropIfExists() to remove the table.

What's Next?

Transactions

Understand how go-migration wraps each migration in a transaction and how to opt out.

Altering Tables

Learn how to modify existing database tables using the Schema Builder's s.Alter() method.

On this page

Creating Tables
Basic Usage
Complete Example
How It Works
What's Next?