Add hasColumn/hasColumns method

[Alex-Belyi]

Add hasColumn/hasColumns method

Checklist

• [x] Add tests and ensure they pass
• [x] Add an entry to the CHANGELOG.md file
• [ ] Update documentation for new features

[alcaeus]

I agree with @GromNaN here. This method is essentially useless, because you're looking for "does any document in this collection have a field with this name". This is not something you should be checking for, and is also an extremely inefficient query as it's usually run unindexed, and thus relies on a collection scan and BSON inspection of every document in the collection.

If there's a specific use case you'd like to change this method for, please share this use case with us, but I don't see any benefit in changing the current implementation.

[Alex-Belyi]

@GromNaN @alcaeus Sorry for late answer.

I want to share example why I added such code.

So I have bitbucket pipelines configured to deploy project to virtual machine There is three options for DB (keep existing, reset all, reset only mysql (keep mongo)).

We use single Laravel project which works with migrations (mysql + mongo)

So there an issue if went to keep mongo DB and reset only mysql

    public function up(): void
    {
        Schema::connection('mongodb')->table('table_name', function (Blueprint $collection) {
            $collection->unique('id');
        });
    }

Will cause an error about existing unique key

so I added some manual 'hasColumn' method to avoid such situation

    public function up(): void
    {
        Schema::connection('mongodb')->table('table_name', function (Blueprint $collection) {
            if (MongoDb::hasColumn('table_name', 'id')) {
                $collection->unique('id');
            }
        });
    }

[GromNaN]

Thanks for taking the time to give a little more context. It seems to me that this use-case does not correspond to the purpose of this method in Laravel. Here are a few comments:

• The fact that the index is created conditionally if there is data in the field or not, seems flaky.
• The state of the database migrations is stored in the database (in a MySQL table and a MongoDB collection), you should be able to rely on the migrations to know the state of your database schema.
• If you want to ignore the error, wrap the $collection->unique('id'); in a try...catch.