![]() Set TIMESTAMP columns to use CURRENT_TIMESTAMP when a record is updated (MySQL).Ĭreate a virtual generated column (MySQL).Ĭreate an identity column with specified sequence options (PostgreSQL).ĭefines the precedence of sequence values over input for an identity column (PostgreSQL). Set TIMESTAMP columns to use CURRENT_TIMESTAMP as default value. Make the column "invisible" to SELECT * queries (MySQL).Īllow NULL values to be inserted into the column.Ĭreate a stored generated column (MySQL / PostgreSQL). Set the starting value of an auto-incrementing field (MySQL / PostgreSQL). Place the column "first" in the table (MySQL). Specify a "default" value for the column. Specify a collation for the column (MySQL/PostgreSQL/SQL Server).Īdd a comment to a column (MySQL/PostgreSQL). Specify a character set for the column (MySQL). Set INTEGER columns as auto-incrementing (primary key). Place the column "after" another column (MySQL). This list does not include index modifiers: Modifier The following table contains all of the available column modifiers. To get started, execute the schema:dump command: If you would like, you may "squash" your migrations into a single SQL file. This can lead to your database/migrations directory becoming bloated with potentially hundreds of migrations. Migration stubs may be customized using stub publishing.Īs you build your application, you may accumulate more and more migrations over time. The given path should be relative to your application's base path. ![]() If you would like to specify a custom path for the generated migration, you may use the -path option when executing the make:migration command. Otherwise, you may simply specify the table in the migration file manually. If Laravel is able to determine the table name from the migration name, Laravel will pre-fill the generated migration file with the specified table. Laravel will use the name of the migration to attempt to guess the name of the table and whether or not the migration will be creating a new table. Php artisan make:migration create_flights_table Each migration filename contains a timestamp that allows Laravel to determine the order of the migrations: The new migration will be placed in your database/migrations directory. You may use the make:migration Artisan command to generate a database migration. Typically, migrations will use this facade to create and modify database tables and columns. ![]() The Laravel Schema facade provides database agnostic support for creating and manipulating tables across all of Laravel's supported database systems. If you have ever had to tell a teammate to manually add a column to their local database schema after pulling in your changes from source control, you've faced the problem that database migrations solve. Alternatively, you can add constraints later (see below) after you've filled in the new column correctly.Migrations are like version control for your database, allowing your team to define and share the application's database schema definition. ![]() Keep in mind however that the default value must satisfy the given constraints, or the ADD will fail. In fact all the options that can be applied to a column description in CREATE TABLE can be used here. ![]() You can also define constraints on the column at the same time, using the usual syntax:ĪLTER TABLE products ADD COLUMN description text CHECK (description '') To avoid a potentially lengthy update operation, particularly if you intend to fill the column with mostly nondefault values anyway, it may be preferable to add the column with no default, insert the correct values using UPDATE, and then add any desired default as described below. However, if the default value is volatile (e.g., clock_timestamp()) each row will need to be updated with the value calculated at the time ALTER TABLE is executed. Instead, the default value will be returned the next time the row is accessed, and applied when the table is rewritten, making the ALTER TABLE very fast even on large tables. From PostgreSQL 11, adding a column with a constant default value no longer means that each row of the table needs to be updated when the ALTER TABLE statement is executed. ![]()
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