Why cursor pl sql

If the cursor declaration declares parameters, each parameter must be used in the query. You must declare a variable before referencing it in a cursor declaration. You cannot assign values to a cursor name or use it in an expression. However, cursors and variables follow the same scoping rules. You retrieve data from a cursor by opening it, then fetching from it.

The scope of cursor parameters is local to the cursor, meaning that they can be referenced only within the query used in the cursor declaration. The values of cursor parameters are used by the associated query when the cursor is opened.

Let's execute the following program to update the table and increase salary of each customer by The Explicit cursors are defined by the programmers to gain more control over the context area.

You can fetch rows from the above-opened cursor as follows:. The following syntax is used to close the above-opened cursors. Let's take an example to demonstrate the use of explicit cursor. JavaTpoint offers too many high quality services.

Mail us on [email protected] , to get more information about given services. Please mail your requirement at [email protected] Duration: 1 week to 2 week.

Reinforcement Learning. R Programming. React Native. Python Design Patterns. Python Pillow. After placing the cursor on a row, they can operate on the row data, such as extracting the data of the current row and so on. Record variables can be defined based on tables and views. Record variables can also be defined based on cursors.

When a record variable is defined based on a cursor, the record member name is actually the column name and the column alias of the SELECT statement. In order to simplify the data processing of display cursors, it is recommended that developers use record variables to store cursor data. For example:. This cursor does not need to be declared, opened, and closed. As with the display cursor, variables with keyword into receive data with the same data type as the list.

We can give the cursor name instead of range limit in the FOR loop statement so that the loop will work from the first record of the cursor to the last record of the cursor.

The cursor variable, opening of cursor, fetching and closing of the cursor will be done implicitly by the FOR loop. Example 1 : In this example, we will project all the employee name from emp table using a cursor-FOR loop. Skip to content. Report a Bug. Previous Prev. Next Continue.

Home Testing Expand child menu Expand. SAP Expand child menu Expand.