*`node.psql(database, query)` - runs query via`psql` command and returns tuple`(error code, stdout, stderr)`

*`node.safe_psql(database, query)` - same as`psql()` except that it returns only`stdout`. If an error occures during the execution, an exception will be thrown.

*`node.execute(database, query)` - connects to postgresql server using`psycopg2` or`pg8000` library (depends on which is installed in your system) and returns two-dimensional array with data.

*`node.execute(database, query, username=None, commit=True)` - connects to postgresql server using`psycopg2` or`pg8000` library (depends on which is installed in your system) and returns two-dimensional array with data.

*`node.connect(database='postgres')` - returns connection wrapper (`NodeConnection`) capable of running several queries within a single transaction.

The last one is the most powerful: you can use`begin(isolation_level)`,`commit()` and`rollback()`:

raiseTimeoutException('Query timeout')

defexecute(self,dbname,query,username=None,commit=False):

defexecute(self,dbname,query,username=None,commit=True):