custom sql migration

db.js

function executeSql (sql, data) {
  if(data != undefined && data.length > 0) {
		var final_sql = sql;
		for(var value in data) {
			final_sql = final_sql.replace(sqlSeperator, '"' + escapeSql(data[value]) + '"');
		}
		return db_instance.execute(final_sql);
	} else {
		return db_instance.execute(sql);
	}
}

function updateTableSchema (schema) {
	Ti.API.debug("db.js: update to schema is needed at table: " + table);
	var row = executeSql("SELECT * FROM '" + table + "' LIMIT 0,1;");
	var columns = "";
	
	// parity issue: https://jira.appcelerator.org/browse/TIMOB-2945
	fc = _.isFunction(rs.fieldCount) ? rs.fieldCount() : rs.fieldCount;
	if(fc > 1) {
		columns = getCommonColumns(schema,row,fc).join();
	}
	row.close();
	
	db_instance.execute('CREATE TEMPORARY TABLE ' + table + '_backup(' + columns + ');')
	db_instance.execute('INSERT INTO ' + table + '_backup SELECT ' + columns + ' FROM ' + table + ';');
	db_instance.execute('DROP TABLE ' + table + ';');
	db_instance.execute(createTableSql(schema));
	db_instance.execute('INSERT INTO ' + table + ' (' + columns + ') SELECT ' + columns + ' FROM ' + table + '_backup;');
	db_instance.execute('DROP TABLE ' + table + '_backup;');
}
function createTableSql(schema) {
	if(schema[0] == "id") {
		db_schema = schema.slice(1, schema.length);
	} else {
		db_schema = schema;
	}
	var sql = 'CREATE TABLE IF NOT EXISTS ' + table + ' (';
	sql += "\n\tid INTEGER PRIMARY KEY";
	for(var field in db_schema) {
		sql += ",\n\t" + db_schema[field] + ' TEXT';
	}
	sql += "\n);";
	return sql;
}