Represents an SQL table in an abstract way for updating a table. Also see TableDefinition and ActiveRecord::ConnectionAdapters::SchemaStatements#create_table
Available transformations are:
change_table :table do |t|
t.column
t.index
t.rename_index
t.timestamps
t.change
t.change_default
t.rename
t.references
t.belongs_to
t.string
t.text
t.integer
t.float
t.decimal
t.datetime
t.timestamp
t.time
t.date
t.binary
t.boolean
t.remove
t.remove_references
t.remove_belongs_to
t.remove_index
t.remove_timestamps
end
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[R] | name |
Changes the column's definition according to the new options. See ActiveRecord::ConnectionAdapters::TableDefinition#column for details of the options you can use.
t.change(:name, :string, limit: 80)
t.change(:description, :text)
Sets a new default value for a column. See ActiveRecord::ConnectionAdapters::SchemaStatements#change_column_default
t.change_default(:qualification, 'new')
t.change_default(:authorized, 1)
Adds a new column to the named table. See ActiveRecord::ConnectionAdapters::TableDefinition#column for details of the options you can use.
Creating a simple column
t.column(:name, :string)
Checks to see if a column exists. See ActiveRecord::ConnectionAdapters::SchemaStatements#column_exists?
Adds a new index to the table. column_name
can be a single Symbol, or an Array of Symbols. See ActiveRecord::ConnectionAdapters::SchemaStatements#add_index
Creating a simple index
t.index(:name)
Creating a unique index
t.index([:branch_id, :party_id], unique: true)
Creating a named index
t.index([:branch_id, :party_id], unique: true, name: 'by_branch_party')
Checks to see if an index exists. See ActiveRecord::ConnectionAdapters::SchemaStatements#index_exists?
Adds a reference.
t.references(:user)
t.belongs_to(:supplier, foreign_key: true)
See ActiveRecord::ConnectionAdapters::SchemaStatements#add_reference for details of the options you can use.
Removes the column(s) from the table definition.
t.remove(:qualification)
t.remove(:qualification, :experience)
Removes the given index from the table.
Remove the index_table_name_on_column in the table_name table
t.remove_index :column
Remove the index named index_table_name_on_branch_id in the table_name table
t.remove_index column: :branch_id
Remove the index named index_table_name_on_branch_id_and_party_id in the table_name table
t.remove_index column: [:branch_id, :party_id]
Remove the index named by_branch_party in the table_name table
t.remove_index name: :by_branch_party
Removes a reference. Optionally removes a type
column.
remove_references
and remove_belongs_to
are
acceptable.
t.remove_references(:user)
t.remove_belongs_to(:supplier, polymorphic: true)
See ActiveRecord::ConnectionAdapters::SchemaStatements#remove_reference
Removes the timestamp columns (created_at
and
updated_at
) from the table.
t.remove_timestamps
Renames a column.
t.rename(:description, :name)
Renames the given index on the table.
t.rename_index(:user_id, :account_id)
Adds timestamps (created_at
and updated_at
)
columns to the table. See ActiveRecord::ConnectionAdapters::SchemaStatements#add_timestamps
t.timestamps null: false