Python has various database drivers for PostgreSQL. Currently, most used version is psycopg2 because it fully implements the Python DB-API 2.0 specification. The psycopg2 provides many useful features such as client-side and server-side cursors, asynchronous notification and communication, COPY command support, etc.
psycopg2 can be downloaded like any other module using the following command:
pip install psycopg2
PostgreSQL’s way of creating Primary key with auto increment feature :
A column has to be defined with SERIAL PRIMARY KEY. Here SERIAL is not a true data type, but is simply shorthand notation that tells Postgres to create an auto incremented, unique identifier for the specified column. By simply setting a column as SERIAL with PRIMARY KEY attached, Postgres will handle all the complicated behind-the-scenes work and automatically increment our the specified column with a unique, primary key value for every INSERT.
Database name: testdb
Table name: EMPLOYEE
In the EMPLOYEE TABLE, column named EMPLOYEE_ID will be implemented as an auto-incremented Primary key column.
CREATE TABLE <table_name>(
<column1_name> SERIAL NOT NULL PRIMARY KEY,
The implementation of creating a table with such specification is given below:
We can see the table created using pgadmin tool
Now, Insertion needs to done to see if our auto-increment feature works or not. This can be done either directly through pgadmin or using python code.
pgadmin way :
Below is the screenshot that shows execution of insert queries and resultant result-set.
Using python code:
Output of employee table after executing above program :
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