MIF_E31222691/laravel/database/schema.php

117 lines
2.9 KiB
PHP

<?php namespace Laravel\Database;
use Laravel\Fluent;
use Laravel\Database as DB;
class Schema {
/**
* Begin a fluent schema operation on a database table.
*
* @param string $table
* @param Closure $callback
* @return void
*/
public static function table($table, $callback)
{
call_user_func($callback, $table = new Schema\Table($table));
static::implications($table);
return static::execute($table);
}
/**
* Execute the given schema operation against the database.
*
* @param Schema\Table $table
* @return void
*/
public static function execute($table)
{
foreach ($table->commands as $command)
{
$connection = DB::connection($table->connection);
$grammar = static::grammar($connection);
// Each grammar has a function that corresponds to the command type and is for
// building that command's SQL. This lets the SQL generation stay granular
// and flexible across various database systems.
if (method_exists($grammar, $method = $command->type))
{
$statements = $grammar->$method($table, $command);
// Once we have the statements, we will cast them to an array even though
// not all of the commands return an array just in case the command
// needs multiple queries to complete its database work.
foreach ((array) $statements as $statement)
{
$connection->statement($statement);
}
}
}
}
/**
* Add any implicit commands to the schema table operation.
*
* @param Schema\Table $table
* @return void
*/
protected static function implications($table)
{
// If the developer has specified columns for the table and the table is
// not being created, we'll assume they simply want to add the columns
// to the table and generate the add command.
if (count($table->columns) > 0 and ! $table->creating())
{
$command = new Fluent(array('type' => 'add'));
array_unshift($table->commands, $command);
}
// For some extra syntax sugar, we'll check for any implicit indexes
// on the table since the developer may specify the index type on
// the fluent column declaration for convenience.
foreach ($table->columns as $column)
{
foreach (array('primary', 'unique', 'fulltext', 'index') as $key)
{
if (isset($column->attributes[$key]))
{
$table->$key($column->name, $column->$key);
}
}
}
}
/**
* Create the appropriate schema grammar for the driver.
*
* @param Connection $connection
* @return Grammar
*/
public static function grammar(Connection $connection)
{
$driver = $connection->driver();
switch ($driver)
{
case 'mysql':
return new Schema\Grammars\MySQL($connection);
case 'pgsql':
return new Schema\Grammars\Postgres($connection);
case 'sqlsrv':
return new Schema\Grammars\SQLServer($connection);
case 'sqlite':
return new Schema\Grammars\SQLite($connection);
}
throw new \Exception("Schema operations not supported for [$driver].");
}
}