public String getPrimaryKeyColumn(String tableName) {
		// FIXME: Currently working for PostgreSQL only
		if (this.dbSystem.equals("POSTGRESQL")) {
			String sqlPrimaryKey = "SELECT a.attname FROM pg_index i JOIN pg_attribute a ON a.attrelid = i.indrelid AND a.attnum = ANY(i.indkey) WHERE i.indrelid = '" + tableName + "'::regclass AND i.indisprimary;";
			return (String) findSingletonValue(sqlPrimaryKey);
		}
		else   // TODO: Handle other JDBC sources
			return null;
	}
public String getPrimaryKeyColumn(String tableName) {
	
		if (this.dbSystem.equals("POSTGRESQL")) {
			String sqlPrimaryKey = "SELECT a.attname FROM pg_index i JOIN pg_attribute a ON a.attrelid = i.indrelid AND a.attnum = ANY(i.indkey) WHERE i.indrelid = '" + tableName + "'::regclass AND i.indisprimary;";
			return (String) findSingletonValue(sqlPrimaryKey);
		}
		else  
			return null;
	}
public string getprimarykeycolumn(string tablename) { if (this.dbsystem.equals("postgresql")) { string sqlprimarykey = "select a.attname from pg_index i join pg_attribute a on a.attrelid = i.indrelid and a.attnum = any(i.indkey) where i.indrelid = '" + tablename + "'::regclass and i.indisprimary;"; return (string) findsingletonvalue(sqlprimarykey); } else return null; }