Examples to Implement in PostgreSQL For Loop. Below are some examples of PostgreSQL For Loop: Example #1. Let us first consider a simple example of printing the table of a particular integer that we pass to our function. Let us begin to be creating our function. Code: CREATE OR REPLACE FUNCTION displayTable(int) RETURNS void AS $$ DECLARE.

John: Those examples are great except there is no way that I know of to loop on the 'top level' as you call it. I'm trying to do something that I can give to psql which will loop through the entire set that is produced. I came across the FOR-IN loop but that needs a function. PostgreSQL provides equivalent ROWCOUNT for the same purpose. REF CURSOR is Oracle data type that represents the cursor, every cursor variable must be defined with a type derived from REF CURSOR. PostgreSQL provides equivalent REFCURSOR for the same purpose. Oracle allows to iterate rows in cursor using the following cycle.

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Cursors In Postgresql Tutorial

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.

Postgresql Cursor For Loop Example Java

Example

Methods

Following are the various methods provided by the Cursor class/object.

Sr.No.	Methods & 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() Plants vs zombies 2 pc version full download. 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	lastrowid 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.

PL/SQL cursor FOR loop has one great advantage of loop continued until row not found. In sometime you require to use explicit cursor with FOR loop instead of use OPEN, FETCH, and CLOSE statement.

FOR loop iterate repeatedly and fetches rows of values from database until row not found.

Explicit Cursor FOR LOOP Example

following one emp_information table:

EMP_NO	EMP_NAME	EMP_DEPT	EMP_SALARY
1	Forbs ross	Web Developer	45k
2	marks jems	Program Developer	38k
3	Saulin	Program Developer	34k
4	Zenia Sroll	Web Developer	42k

Display employee number wise first two employee details emp,

Example

Postgresql Cursor With Hold

cursor_for_loop.sql

Result

SQL>@cursor_for_loop
EMP_No: 1
EMP_Name: Forbs ross
EMP_Dept: Web Developer
EMP_Salary:45k
EMP_No: 2
EMP_Name: marks jems
EMP_Dept: Program Developer
EMP_Salary:38k
PL/SQL procedure successfully completed.

Cursors In Postgresql Tutorial

Postgresql Cursor For Loop Example Java

Example

Methods

Properties

Explicit Cursor FOR LOOP Example

Postgresql Cursor With Hold

Postgresql Cursor For Loop Example Sentences

Postgresql Function For Loop