add column unique numbering scheme, more efficient selects

database/migrations/2018_08_01_204822_add_row_sequence_generator.php

@@ -30,7 +30,7 @@ END;
 $$ LANGUAGE 'plpgsql';
 PGSQL
 );
-        DB::unprepared('CREATE SEQUENCE global_row_id_seq START 0 MINVALUE 0;');
+        DB::unprepared('CREATE SEQUENCE IF NOT EXISTS global_row_id_seq  START 0 MINVALUE 0;');
         // We have to increment manually once before the above function can be used - that is because
         // nextval will return the initial value the first time it's called, so it would not advance by
         // the given step at all. This would give us negative values - not a problem in postgres without unsigned

database/migrations/2018_08_01_213353_make_grid_column_mandatory_in_rows_table.php

@@ -13,7 +13,7 @@ class MakeGridColumnMandatoryInRowsTable extends Migration
      */
     public function up()
     {
-        DB::unprepared("ALTER TABLE rows ADD CONSTRAINT grid_must_exist CHECK (data ? '_grid');");
+        DB::unprepared("ALTER TABLE rows ADD CONSTRAINT grid_must_exist CHECK (data ? '_id');");
     }
 
     /**

database/migrations/2018_08_04_165815_add_column_sequence.php

@@ -0,0 +1,30 @@
+<?php
+
+use Illuminate\Support\Facades\Schema;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Database\Migrations\Migration;
+
+class AddColumnSequence extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        DB::unprepared('CREATE SEQUENCE IF NOT EXISTS global_column_id_seq START 0 MINVALUE 0;');
+        // mandatory first increment to make the multi_nextval function work
+        DB::select("SELECT nextval('global_column_id_seq') as nv;");
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        DB::unprepared('DROP SEQUENCE IF EXISTS global_column_id_seq;');
+    }
+}