Creates a new table instance.

• @param table_name [Symbol] The name of the table
• @param schema [Schema] The schema this table belongs to
• @param as_name [String, nil] An optional alias for the table
• @raise [Error] If the table name is invalid

Example

table = Table.new(:users, schema)
table = Table.new(:users, schema, as: "user_table")

Adds a new column to the table.

• @param columns [Array(Symbol)] the columns to be indexed
• @param unique [Bool] whether the index should be unique (default: false)
• @param table [Table] the table to add the index to (default: self)
• @return [Index] the new index

Example Adding a new index

add_index([:email], unique: true)
add_index([:email, :username], unique: true)
add_index([:email, :username], unique: true, table: users)

Adds a new column to the table.

• @param name [Symbol] the name of the column to be added
• @param as_name [String, nil] an optional alias for the column
• @param null [Bool] whether the column allows null values (default: false)
• @param default [DB::Any, nil] the default value for the column (default: nil)
• @param unique [Bool] whether the column should have a unique constraint (default: false)
• @param index [Bool] whether the column should be indexed (default: false)
• @return [Column] the new column

Example Adding a new column with default options

bigint :age
bigint :age, as: "user_age", null: false, default: 18, unique: true, index: true

Adds a new column to the table.

• @param name [Symbol] the name of the column to be added
• @param as_name [String, nil] an optional alias for the column
• @param null [Bool] whether the column allows null values (default: false)
• @param default [DB::Any, nil] the default value for the column (default: nil)
• @param unique [Bool] whether the column should have a unique constraint (default: false)
• @param index [Bool] whether the column should be indexed (default: false)
• @return [Column] the new column

Example Adding a new column with default options

blob :data
blob :data, as: "binary_data", null: false, default: nil, unique: true, index: true

Adds a new column to the table.

• @param name [Symbol] the name of the column to be added
• @param as_name [String, nil] an optional alias for the column
• @param null [Bool] whether the column allows null values (default: false)
• @param default [DB::Any, nil] the default value for the column (default: nil)
• @param unique [Bool] whether the column should have a unique constraint (default: false)
• @param index [Bool] whether the column should be indexed (default: false)
• @return [Column] the new column

Example Adding a new column with default options

boolean :active
boolean :active, as: "is_active", null: false, default: false, unique: true, index: true

Adds a CHECK constraint to the table.

• @param condition [String] The SQL condition for the check constraint.
• @param name [String, nil] Optional name for the constraint.
• @return [CheckConstraint] The created check constraint object.

Example

check_constraint "price > 0"
check_constraint "email LIKE '%@%'", name: "chk_email_format"

Adds a new column to the table.

• @param name [Symbol] the name of the column to be added
• @param type [T.class] the data type of the column
• @param as_name [String, nil] an optional alias for the column
• @param null [Bool] whether the column allows null values (default: false)
• @param default [DB::Any, nil] the default value for the column (default: nil)
• @param unique [Bool] whether the column should have a unique constraint (default: false)
• @param size [Int32, nil] the size of the column (default: nil)
• @param index [Bool] whether the column should be indexed (default: false)
• @return [Column] the new column

Example Adding a new column with default options

column :email, String

Creates the table in the database.

• @return [Nil]

Example

table = Table.new(:users, schema)
table.column(:id, Int64, primary: true)
table.column(:name, String)
table.create!
=> nil

Generates the SQL to create the table. Includes column definitions and foreign key constraints.

Adds a new column to the table.

• @param name [Symbol] the name of the column to be added
• @param as_name [String, nil] an optional alias for the column
• @param null [Bool] whether the column allows null values (default: false)
• @param default [DB::Any, nil] the default value for the column (default: nil)
• @param unique [Bool] whether the column should have a unique constraint (default: false)
• @param index [Bool] whether the column should be indexed (default: false)
• @return [Column] the new column

Example Adding a new column with default options

date :birthday
date :birthday, as: "date_of_birth", null: false, default: Time.local, unique: true, index: true

Adds a new column to the table.

• @param name [Symbol] the name of the column to be added
• @param as_name [String, nil] an optional alias for the column
• @param null [Bool] whether the column allows null values (default: false)
• @param default [DB::Any, nil] the default value for the column (default: nil)
• @param unique [Bool] whether the column should have a unique constraint (default: false)
• @param index [Bool] whether the column should be indexed (default: false)
• @return [Column] the new column

Example Adding a new column with default options

double :age
double :age, as: "user_age", null: false, default: 18.0, unique: true, index: true

Drops the table from the database.

• @return [Nil]

Example

table = Table.new(:users, schema)
table.drop!
=> nil

Generates the SQL to drop the table.

• @return [String] the SQL query

Example

table = Table.new(:users, schema)
table.drop_sql

=> "DROP TABLE users;"

Gets table expression for Sql query generation

• @return [Expression::Table] the table expression

Example

table = Table.new(:users, schema)
table.expression
=> #<Expression::Table:0x00007f8e7a4e1e80>

Adds a new column to the table.

• @param name [Symbol] the name of the column to be added
• @param as_name [String, nil] an optional alias for the column
• @param null [Bool] whether the column allows null values (default: false)
• @param default [DB::Any, nil] the default value for the column (default: nil)
• @param unique [Bool] whether the column should have a unique constraint (default: false)
• @param index [Bool] whether the column should be indexed (default: false)
• @return [Column] the new column

Example Adding a new column with default options

float :age
float :age, as: "user_age", null: false, default: 18.0, unique: true, index: true

Adds a foreign key constraint to the table.

• @param columns [Array(Symbol), Symbol] The column(s) in this table.
• @param references_table [Symbol] The table the foreign key references.
• @param references_columns [Array(Symbol), Symbol, nil] The column(s) in the referenced table. Defaults to the primary key of the referenced table if nil.
• @param name [String, nil] Optional name for the constraint.
• @param on_delete [Symbol] Action on delete (:cascade, :restrict, :set_null, :no_action). Default :no_action.
• @param on_update [Symbol] Action on update (:cascade, :restrict, :set_null, :no_action). Default :no_action.
• @return [ForeignKey] The created foreign key object.

Example

# Simple foreign key referencing the primary key of 'users'
foreign_key :user_id, references: :users

# Foreign key with explicit referenced column and ON DELETE CASCADE
foreign_key :author_id, references: :authors, references_columns: :id, on_delete: :cascade

# Composite foreign key
foreign_key [:order_id, :product_id], references: :order_items, references_columns: [:o_id, :p_id]

Overload to accept a single column symbol

Adds a new column to the table.

• @param name [Symbol] the name of the column to be added
• @param as_name [String, nil] an optional alias for the column
• @param null [Bool] whether the column allows null values (default: false)
• @param default [DB::Any, nil] the default value for the column (default: nil)
• @param unique [Bool] whether the column should have a unique constraint (default: false)
• @param index [Bool] whether the column should be indexed (default: false)
• @return [Column] the new column

Example Adding a new column with default options

integer :age
integer :age, as: "user_age", null: false, default: 18, unique: true, index: true

Adds a new column to the table.

• @param name [Symbol] the name of the column to be added
• @param as_name [String, nil] an optional alias for the column
• @param null [Bool] whether the column allows null values (default: false)
• @param default [DB::Any, nil] the default value for the column (default: nil)
• @param unique [Bool] whether the column should have a unique constraint (default: false)
• @param index [Bool] whether the column should be indexed (default: false)
• @return [Column] the new column

Example Adding a new column with default options

interval :duration
interval :duration, as: "time_span", null: false, default: Time.local, unique: true, index: true

Adds a new JSON column to the table.

• @param name [Symbol] the name of the column to be added
• @param type [T.class] the Crystal type to map the JSON to (default: JSON::Any)
• @param as_name [String, nil] an optional alias for the column
• @param null [Bool] whether the column allows null values (default: false)
• @param default [DB::Any, nil] the default value for the column (default: nil)
• @param unique [Bool] whether the column should have a unique constraint (default: false)
• @param index [Bool] whether the column should be indexed (default: false)
• @return [Column] the new column

Example Adding a new column with default options

# Defaults to JSON::Any
json :metadata

# Using a custom type
class MySettings
  include JSON::Serializable
  property theme : String
end

json :settings, MySettings

json :metadata, JSON::Any, as: "meta", null: false, default: nil, unique: true, index: true

Adds a new primary key column to the table.

• @param name [Symbol] the name of the column to be added (default: :id)
• @param type [T.class] the data type of the column (default: Int32)
• @param auto_increment [Bool] whether the column should auto increment (default: true)
• @param as_name [String, nil] an optional alias for the column
• @param unique [Bool] whether the column should have a unique constraint (default: true)
• @return [PrimaryKey(T)] the new primary key column

Example Adding a new primary key column

primary :id, Int32
primary :id, Int32, auto_increment: false

Adds a new column to the table.

• @param name [Symbol] the name of the column to be added
• @param as_name [String, nil] an optional alias for the column
• @param null [Bool] whether the column allows null values (default: false)
• @param default [DB::Any, nil] the default value for the column (default: nil)
• @param unique [Bool] whether the column should have a unique constraint (default: false)
• @param index [Bool] whether the column should be indexed (default: false)
• @return [Column] the new column

Example Adding a new column with default options

decimal :price
decimal :price, as: "product_price", null: false, default: 0.0, unique: true, index: true

Adds a new column to the table.

• @param name [Symbol] the name of the column to be added
• @param as_name [String, nil] an optional alias for the column
• @param null [Bool] whether the column allows null values (default: false)
• @param default [DB::Any, nil] the default value for the column (default: nil)
• @param unique [Bool] whether the column should have a unique constraint (default: false)
• @param index [Bool] whether the column should be indexed (default: false)
• @return [Column] the new column

Example Adding a new column with default options

timestamp :created_at
timestamp :created_at, as: "created_at", null: false, default: Time.local, unique: true, index: true

Adds a new column to the table.

Example Adding timestamps to the table

timestamps

Truncates the table in the database.

• @return [Nil]

Example

table = Table.new(:users, schema)
table.truncate!
=> nil

Generates the SQL to truncate the table.

• @return [String] the SQL query

Example

table = Table.new(:users, schema)
table.truncate_sql
=> "TRUNCATE TABLE users;"

Adds a UNIQUE constraint to the table.

• @param columns [Array(Symbol)] The column(s) to include in the constraint.
• @param name [String, nil] Optional name for the constraint.
• @return [UniqueConstraint] The created unique constraint object.

Example

unique_constraint [:email]
unique_constraint [:first_name, :last_name], name: "uk_person_name"

Adds a new column to the table.

• @param name [Symbol] the name of the column to be added