How to get a column's default value using Laravel? - php

Question

I am building a custom artisan command that needs to be able to access the database's default values for certain columns. I cannot use the attributes array. So instead I need another way.
I have tried to use Schema. I have been able to get the table DB::table($table) and the column names Schema::getColumnListings($table) but not the default values.
Is there some other way to get the default values?

Answer 1

The Laravel Schema Builder only returns column names by design. But you can use the same approach Laravel uses internally by executing a database statement:
$results = DB::select('
select column_default
from information_schema.columns
where
table_schema = ?
and table_name = ?
', [$database, $table]);
// Flatten the results to get an array of the default values
$defaults = collect($results)->pluck('column_default'))
The above example works for a MySQL database, but you can see the approaches for other databases in the Illuminate\Database\Schema\Grammars namespace of the Laravel source code by searching for the method compileColumnListing.

Answer 2

In Laravel 5+ (including 6 and 7), you can get the db table column metadata (ie type, default value etc) in the following way:
use Illuminate\Support\Facades\Schema;
For all columns:
$columns = Schema::getConnection()->getDoctrineSchemaManager()->listTableColumns('table_name');
For a single column:
$column = Schema::getConnection()->getDoctrineColumn('table_name'', 'column_name');
getDoctrineSchemaManager method returns a array of \Doctrine\DBAL\Schema\Column Class Instances. By using this you can get everything about a db table column.
getDoctrineColumn method returns the instance of \Doctrine\DBAL\Schema\Column class.
Couple of methods from \Doctrine\DBAL\Schema\Column class:
$column->getName();
$column->getNotnull(); // returns true/false
$column->getDefault();
$column->getType();
$column->getLength();