schema.md

# Schema Builder

## Contents

- [The Basics](#the-basics)
- [Creating & Dropping Tables](#creating-dropping-tables)
- [Adding Columns](#adding-columns)
- [Dropping Columns](#dropping-columns)
- [Adding Indexes](#adding-indexes)
- [Dropping Indexes](#dropping-indexes)
- [Foreign Keys](#foreign-keys)

<a name="the-basics"></a>
## The Basics

The Schema Bulder provides methods for creating and modifying your database tables. Using a fluent syntax, you can work with your tables without using any vendor specific SQL.

*Further Reading:*

- [Migrations](/docs/database/migrations)

<a name="creating-dropping-tables"></a>
## Creating & Dropping Tables

The **Schema** class is used to create and modify tables. Let's jump right into an example:

#### Creating a simple database table:

	Schema::create('users', function($table)
	{
		$table->increments('id');
	});

Let's go over this example. The **create** method tells the Schema builder that this is a new table, so it should be created. In the second argument, we passed a Closure which receives a Table instance. Using this Table object, we can fluently add and drop columns and indexes on the table.

#### Dropping a table from the database:

	Schema::drop('users');

Sometimes you may need to specify the database connection on which the schema operation should be performed.

#### Specifying the connection to run the operation on:

	Schema::create('users', function($table)
	{
		$table->on('connection');
	});

<a name="adding-columns"></a>
## Adding Columns

The fluent table builder's methods allow you to add columns without using vendor specific SQL. Let's go over it's methods:

Command  | Description
------------- | -------------
`$table->increments('id');`  |  Incrementing ID to the table
`$table->string('email');`  |  VARCHAR equivalent column
`$table->string('name', 100);`  |  VARCHAR equivalent with a length
`$table->integer('votes');`  |  INTEGER equivalent to the table
`$table->float('amount');`  |  FLOAT equivalent to the table
`$table->boolean('confirmed');`  |  BOOLEAN equivalent to the table
`$table->date('created_at');`  |  DATE equivalent to the table
`$table->timestamp('added_on');`  |  TIMESTAMP equivalent to the table
`$table->timestamps();`  |  Adds **created\_at** and **updated\_at** columns
`$table->text('description');`  |  TEXT equivalent to the table
`$table->blob('data');`  |  BLOB equivalent to the table
`->nullable()`  |  Designate that the column allows NULL values

> **Note:** Laravel's "boolean" type maps to a small integer column on all database systems.

#### Example of creating a table and adding columns

	Schema::table('users', function($table)
	{
		$table->create();
		$table->increments('id');
		$table->string('username');
		$table->string('email');
		$table->string('phone')->nullable();
		$table->text('about');
		$table->timestamps();
	});

<a name="dropping-columns"></a>
## Dropping Columns

#### Dropping a column from a database table:

	$table->drop_column('name');

#### Dropping several columns from a database table:

	$table->drop_column(array('name', 'email'));

<a name="adding-indexes"></a>
## Adding Indexes

The Schema builder supports several types of indexes. There are two ways to add the indexes. Each type of index has its method; however, you can also fluently define an index on the same line as a column addition. Let's take a look:

#### Fluently creating a string column with an index:

	$table->string('email')->unique();

If defining the indexes on a separate line is more your style, here are example of using each of the index methods:

Command  | Description
------------- | -------------
`$table->primary('id');`  |  Adding a primary key
`$table->primary(array('fname', 'lname'));`  |  Adding composite keys
`$table->unique('email');`  |  Adding a unique index
`$table->fulltext('description');`  |  Adding a full-text index
`$table->index('state');`  |  Adding a basic index

<a name="dropping-indexes"></a>
## Dropping Indexes

To drop indexes you must specify the index's name. Laravel assigns a reasonable name to all indexes. Simply concatenate the table name and the names of the columns in the index, then append the type of the index. Let's take a look at 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
`$table->drop_fulltext('profile_description_fulltext');`  |  Dropping a full-text index from the "profile" table
`$table->drop_index('geo_state_index');`  |  Dropping a basic index from the "geo" table

<a name="foreign-keys"></a>
## Foreign Keys

You may easily add foreign key constraints to your table using Schema's fluent interface. For example, let's assume you have a **user_id** on a **posts** table, which references the **id** column of the **users** table. Here's how to add a foreign key constraint for the column:

	$table->foreign('user_id')->references('id')->on('users');

You may also specify options for the "on delete" and "on update" actions of the foreign key:

	$table->foreign('user_id')->references('id')->on('users')->on_delete('restrict');

	$table->foreign('user_id')->references('id')->on('users')->on_update('cascade');

You may also easily drop a foreign key constraint. The default foreign key names follow the [same convention](#dropping-indexes) as the other indexes created by the Schema builder. Here's an example:

	$table->drop_foreign('posts_user_id_foreign');