[10.x] Get columns of a table

[hafezdivandari]

Previous attempt (PR #45598) was a breaking change and tabled a few days before Laravel 10 release. This PR has more features than the previous one and is not a breaking change.

Usage

Schema::getColumns()

• name (string): Name of the column
• type_name (string): Type name
• type (string): Full definition of the column type
• collation (?string): Collation of the column
• nullable (boolean): Is column nullable?
• default (?string): Default expression of the column if defined
• auto_increment (boolean): Does column auto increment?
• comment (?string): Comment of the column if exists
• generation (null|array) (added on Laravel 11 via [11.x] Add support for modifying generated columns #50329):
  • type (string): Generation type: 'stored' or 'virtual'.
  • expression (string): Generation expression.

Changes

This PR:

1. Adds a new Schema::getColumns():
   Currently, we are using doctrine/dbal to get columns of a table and their attributes, for example on model:show artisan command. This PR adds Schema::getColumns($table) for MySQL, PostgreSQL, SQLite and SQL Server without Doctrine DBAL type mapping issues and full support for all native types. This function returns a list of columns and their attributes:

   use Illuminate\Support\Facades\Schema;
   
   Schema::getColumns('products');
   
    /*
        [
            'name' => 'id',
            'type_name' => 'bigint',
            'type' => 'bigint unsigned,
            'collation' => null,
            'nullable' => false,
            'default' => null,
            'auto_increment' => true,
            'comment' => null,
        ], [
            'name' => 'name',
            'type_name' => 'varchar',
            'type' => 'varchar(255)',
            'collation' => 'utf8mb4_0900_ai_ci',
            'nullable' => false,
            'default' => null,
            'auto_increment' => false,
            'comment' => 'The product name',
        ], [
            'name' => 'status',
            'type_name' => 'enum',
            'type' => "enum('in_stock','out_of_stock')",
            'collation' => 'utf8mb4_0900_ai_ci',
            'nullable' => true,
            'default' => null,
            'auto_increment' => false,
            'comment' =>null,
        ],
    */

2. Adds native support for Schema::getColumnType():
   Currently we are using Doctrine DBAL to get column type using Schema::getColumnType method. DBAL maps every native column type to its Doctrine type equivalent and doesn't support many column types used by Laravel on different databases.

   After this PR you won't need to install doctrine/dbal to get type of a column, you'll be able to get eighter data type name or full type definition of the given column:

   Schema::getColumnType('products', 'id');           // bigint
   Schema::getColumnType('products', 'id', true);     // bigint unsigned
   Schema::getColumnType('products', 'status');       // enum
   Schema::getColumnType('products', 'status', true); // enum('active','suspended','deleted')
   Schema::getColumnType('products', 'name');         // varchar
   Schema::getColumnType('products', 'name', true);   // varchar(255)
   Schema::getColumnType('products', 'price');        // decimal
   Schema::getColumnType('products', 'price', true);  // decimal(8,2)

   Just like [10.x] Add support for native column modifying #45487, if you have already installed doctrine/dbal, you have to call Schema::useNativeSchemaOperationsIfPossible() method within the boot method of your App\Providers\AppServiceProvider class to be able to use native schema operations.

3. Deprecates a few functions:
   This PR makes Schema::getColumnListing() function to use newly added Schema::getColumns() method under the hood, so we don't need any of the following functions any more. This PR deprecates:

   • \Illuminate\Database\Query\Processors\Processor::processColumnListing
   • \Illuminate\Database\Query\Processors\MySqlProcessor::processColumnListing
   • \Illuminate\Database\Query\Processors\PostgresProcessor::processColumnListing
   • \Illuminate\Database\Query\Processors\SQLiteProcessor::processColumnListing
   • \Illuminate\Database\Query\Processors\SqlServerProcessor::processColumnListing
   • \Illuminate\Database\Schema\Grammars\MySqlGrammar::compileColumnListing
   • \Illuminate\Database\Schema\Grammars\PostgresGrammar::compileColumnListing
   • \Illuminate\Database\Schema\Grammars\SQLiteGrammar::compileColumnListing
   • \Illuminate\Database\Schema\Grammars\SqlServerGrammar::compileColumnListing

[morloderex]

@hafezdivandari I am curious about the third point if I haven't add Schema::useNativeSchemaOperationsIfPossible() shouldn't we still use Processor's processColumnListing method in order to be fully backwards compatible with the doctrine/dbal since it looks like the processing from doctrine/dbal was implemented differently than this new native type column types implementation?

Am i missing something here?

[hafezdivandari]

@morloderex These are separated matters, you have to call Schema::useNativeSchemaOperationsIfPossible() if you have doctrine/dbal installed and want to use native Schema::getColumnType(), it's not related to processColumnListing that were used on Schema::getColumnListing before this PR. It's fully backward compatible right now.

Feature	Before	After
Schema::getColumns()	(N/A)	Calls Grammar::compileColumns and Processor::processColumns
Schema::getColumnListing()	Calls Grammar::compileColumnListing and Processor::processColumnListing	Uses Schema::getColumns()
Schema::getColumnType()	Uses doctrine/dbal	Uses doctrine/dbal if installed (for backward compatibility) otherwise uses Schema::getColumns()