merge if not exist

Signed-off-by: Tobias Gurtzick <magic@wizardtales.com>

index.js

@@ -89,12 +89,38 @@ var PgDriver = Base.extend({
  createDatabase: function (dbName, options, callback) {
  var spec = '';
 
- if (typeof options === 'function') callback = options;
+ if (typeof options === 'function') {
+ callback = options;
+ options = {};
+ }
 
- this.runSql(
- util.format('CREATE DATABASE %s %s', this.escapeDDL(dbName), spec),
- callback
- );
+ if (options.ifNotExists) {
+ this.runSql(
+ `
+ DO
+ $do$
+ DECLARE
+ _db TEXT := '${ dbName }';
+ BEGIN
+ CREATE EXTENSION IF NOT EXISTS dblink;
+ IF EXISTS (SELECT 1 FROM pg_database WHERE datname = _db) THEN
+ RAISE NOTICE 'Database "%" already exists, skipping creation.', _db;
+ ELSE
+ PERFORM dblink_connect('dbname=' || current_database());
+ PERFORM dblink_exec('CREATE DATABASE ' || _db || ' ${ spec }');
+ END IF;
+ END
+ $do$
+ `,
+ callback
+ );
+ }
+ else {
+ this.runSql(
+ util.format('CREATE DATABASE %s %s', this.escapeDDL(dbName), spec),
+ callback
+ );
+ }
  },
 
  dropDatabase: function (dbName, options, callback) {