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The Cursor class of the psycopg library provide methods to execute the PostgreSQL commands in the database using python code.
Using the methods of it you can execute SQL statements, fetch data from the result sets, call procedures.
You can create Cursor object using the cursor() method of the Connection object/class.
Example
import psycopg2 #establishing the connection conn = psycopg2.connect( database="mydb", user=''postgres'', password=''password'', host=''127.0.0.1'', port= ''5432'' ) #Setting auto commit false conn.autocommit = True #Creating a cursor object using the cursor() method cursor = conn.cursor()
Methods
Following are the various methods provided by the Cursor class/object.
| Sr.No | Method & Description |
|---|---|
| 1 |
callproc()
This method is used to call existing procedures PostgreSQL database. |
| 2 |
close()
This method is used to close the current cursor object. |
| 3 |
executemany()
This method accepts a list series of parameters list. Prepares an MySQL query and executes it with all the parameters. |
| 4 |
execute() This method accepts a MySQL query as a parameter and executes the given query. |
| 5 |
fetchall()
This method retrieves all the rows in the result set of a query and returns them as list of tuples. (If we execute this after retrieving few rows it returns the remaining ones) |
| 6 |
fetchone()
This method fetches the next row in the result of a query and returns it as a tuple. |
| 7 |
fetchmany()
This method is similar to the fetchone() but, it retrieves the next set of rows in the result set of a query, instead of a single row. |
Properties
Following are the properties of the Cursor class −
| Sr.No | Property & Description |
|---|---|
| 1 |
description
This is a read only property which returns the list containing the description of columns in a result-set. |
| 2 |
astrowid
This is a read only property, if there are any auto-incremented columns in the table, this returns the value generated for that column in the last INSERT or, UPDATE operation. |
| 3 |
rowcount
This returns the number of rows returned/updated in case of SELECT and UPDATE operations. |
| 4 |
closed
This property specifies whether a cursor is closed or not, if so it returns true, else false. |
| 5 |
connection
This returns a reference to the connection object using which this cursor was created. |
| 6 |
name
This property returns the name of the cursor. |
| 7 |
scrollable
This property specifies whether a particular cursor is scrollable. |
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