kohana-schema:这是Laravels Schema库到Kohana的移植。 它提供了一种与数据库无关的操作表的方式。

# This is a port of Laravels Schema library to Kohana. --- - [Introduction](#introduction) - [Creating & Dropping Tables](#creating-and-dropping-tables) - [Adding Columns](#adding-columns) - [Renaming Columns](#renaming-columns) - [Dropping Columns](#dropping-columns) - [Checking Existence](#checking-existence) - [Adding Indexes](#adding-indexes) - [Foreign Keys](#foreign-keys) - [Dropping Indexes](#dropping-indexes) - [Storage Engines](#storage-engines) <a name="introduction" rel='nofollow' onclick='return false;'></a> ## Introduction The Kohana `Schema` class provides a database agnostic way of manipulating tables. It works well with all of the databases supported by Kohana, and has a unified API across all of these systems. <a name="creating-and-dropping-tables" rel='nofollow' onclick='return false;'></a> ## Creating & Dropping Tables To create a new database table, the `Schema::create` method is used: Schema::create('users', function($table) { $table->increments('id'); }); The first argument passed to the `create` method is the name of the table, and the second is a `Closure` which will receive a `Blueprint` object which may be used to define the new table. To rename an existing database table, the `rename` method may be used: Schema::rename($from, $to); To specify which connection the schema operation should take place on, pass a third parameter to the method: Schema::create('users', function($table) { $table->increments('id'); }, 'default'); To drop a table, you may use the `Schema::drop` method: Schema::drop('users'); <a name="adding-columns" rel='nofollow' onclick='return false;'></a> ## Adding Columns To update an existing table, we will use the `Schema::table` method: Schema::table('users', function($table) { $table->string('email'); }); <a name="modifying-columns" rel='nofollow' onclick='return false;'></a> ## Modifying Columns To modify columns in an existing table, we will use the `Schema::table` method: Schema::table('users', function($table) { $table->modify_column('email', 'string', ['length' => '50']); }); > **Note:** Modifying columns is not supported in SQLite. The table builder contains a variety of column types that you may use when building your tables: Command | Description ------------- | ------------- `$table->big_increments('id');` | Incrementing ID using a "big integer" equivalent. `$table->big_integer('votes');` | BIGINT equivalent to the table `$table->binary('data');` | BLOB equivalent to the table `$table->boolean('confirmed');` | BOOLEAN equivalent to the table `$table->date('created_at');` | DATE equivalent to the table `$table->datetime('created_at');` | DATETIME equivalent to the table `$table->decimal('amount', 5, 2);` | DECIMAL equivalent with a precision and scale `$table->double('column', 15, 8);` | DOUBLE equivalent with precision `$table->enum('choices', array('foo', 'bar'));` | ENUM equivalent to the table `$table->float('amount');` | FLOAT equivalent to the table `$table->increments('id');` | Incrementing ID to the table (primary key). `$table->integer('votes');` | INTEGER equivalent to the table `$table->long_text('description');` | LONGTEXT equivalent to the table `$table->medium_text('description');` | MEDIUMTEXT equivalent to the table `$table->morphs('taggable');` | Adds INTEGER `taggable_id` and STRING `taggable_type` `$table->small_integer('votes');` | SMALLINT equivalent to the table `$table->tiny_integer('numbers');` | TINYINT equivalent to the table `$table->soft_deletes();` | Adds **deleted\_at** column for soft deletes `$table->string('email');` | VARCHAR equivalent column `$table->string('name', 100);` | VARCHAR equivalent with a length `$table->text('description');` | TEXT equivalent to the table `$table->time('sunrise');` | TIME equivalent to the table `$table->timestamp('added_on');` | TIMESTAMP equivalent to the table `$table->timestamps();` | Adds **created\_at** and **updated\_at** columns `->nullable()` | Designate that the column allows NULL values `->default($value)` | Declare a default value for a column `->unsigned()` | Set INTEGER to UNSIGNED If you are using the MySQL database, you may use the `after` method to specify the order of columns: #### Using After On MySQL $table->string('name')->after('email'); <a name="renaming-columns" rel='nofollow' onclick='return false;'></a> ## Renaming Columns To rename a column, you may use the `rename_column` method on the Schema builder. Before renaming a column, be sure to add the `doctrine/dbal` dependency to your `composer.json` file. #### Renaming A Column Schema::table('users', function($table) { $table->rename_column('from', 'to'); }); > **Note:** Renaming `enum` column types is not supported. <a name="dropping-columns" rel='nofollow' onclick='return false;'></a> ## Dropping Columns #### Dropping A Column From A Database Table Schema::table('users', function($table) { $table->drop_column('votes'); }); #### Dropping Multiple Columns From A Database Table Schema::table('users', function($table) { $table->drop_column('votes', 'avatar', 'location'); }); <a name="adding-indexes" rel='nofollow' onclick='return false;'></a> ## Adding Indexes The schema builder supports several types of indexes. There are two ways to add them. First, you may fluently define them on a column definition, or you may add them separately: #### Fluently Creating A Column And Index $table->string('email')->unique(); Or, you may choose to add the indexes on separate lines. Below is a list of all available index types: Command | Description ------------- | ------------- `$table->primary('id');` | Adding a primary key `$table->primary(array('first', 'last'));` | Adding composite keys `$table->unique('email');` | Adding a unique index `$table->index('state');` | Adding a basic index <a name="foreign-keys" rel='nofollow' onclick='return false;'></a> ## Foreign Keys Laravel also provides support for adding foreign key constraints to your tables: #### Adding A Foreign Key To A Table $table->foreign('user_id')->references('id')->on('users'); In this example, we are stating that the `user_id` column references the `id` column on the `users` table. You may also specify options for the "on delete" and "on update" actions of the constraint: $table->foreign('user_id') ->references('id')->on('users') ->on_delete('cascade'); To drop a foreign key, you may use the `drop_foreign` method. A similar naming convention is used for foreign keys as is used for other indexes: $table->drop_foreign('posts_user_id_foreign'); > **Note:** When creating a foreign key that references an incrementing integer, remember to always make the foreign key column `unsigned`. <a name="dropping-indexes" rel='nofollow' onclick='return false;'></a> ## Dropping Indexes To drop an index you must specify the index's name. Laravel assigns a reasonable name to the indexes by default. Simply concatenate the table name, the names of the column in the index, and the index type. Here are some examples: Command | Description ------------- | ------------- `$table->drop_primary('users_id_primary');` | Dropping a primary key from the "users" table `$table->drop_unique('users_email_unique');` | Dropping a unique index from the "users" table `$table->drop_index('geo_state_index');` | Dropping a basic index from the "geo" table <a name="storage-engines" rel='nofollow' onclick='return false;'></a> ## Storage Engines To set the storage engine for a table, set the `engine` property on the schema builder: Schema::create('users', function($table) { $table->engine = 'InnoDB'; $table->string('email'); });