Using Psycopg to Connect to a Database¶
Psycopg is a Python API used to execute SQL statements and provides a unified access API for PostgreSQL and GaussDB databases. It is designed for applications that perform data operations. Psycopg 2 is mostly implemented in C as a libpq wrapper, which is efficient and secure. It provides client-side and server-side cursors, asynchronous communication and notification, and COPY TO and COPY FROM functions. Many Python types are out-of-the-box and adapted to matching PostgreSQL data types. Adaptation can be extended and customized with a flexible object adaptation system. Psycopg2 is compatible with Unicode and Python 3.
GaussDB supports Psycopg2 features and allows Psycopg2 to be connected in SSL mode.
Operating System | Platform |
|---|---|
EulerOS 2.5 | x86_64 |
EulerOS 2.8 | ARM64 |
Obtaining the Driver Package¶
Download the GaussDB driver package GaussDB_opengauss_client_tools.zip.
Prerequisites¶
A Python development environment has been installed on the local PC.
You have obtained and decompressed the Python driver package. The package contains the following folders:
psycopg2: psycopg2 library file
lib: lib library file.
Before using the driver, perform the following operations:
Decompress the driver package of the corresponding version and copy psycopg2 to the site-packages folder in the Python installation directory as user root.
Change the psycopg2 directory permission to 755.
Add the psycopg2 directory to the environment variable $PYTHONPATH and validate it.
For non-database users, add the lib directory after decompression to LD_LIBRARY_PATH.
Load the following database driver before creating a database connection.
import psycopg2
Connecting a Database¶
Use the .ini file (the configparser package of Python can parse this type of configuration file) to save the configuration information about the database connection.
Use the psycopg2.connect function to obtain the connection object.
Use the connection object to create a cursor object.