What are the types of cursor in PL SQL?
PL/SQL has two types of cursors: implicit cursors and explicit cursors.
How do I use two cursors in PL SQL?
DECLARE AA NUMBER; CURSOR S IS SELECT ENAME, SAL FROM EMP; CURSOR D IS SELECT ENAME, SAL FROM EMP; NAME EMP. ENAME%TYPE; SALARY EMP. SAL%TYPE; C NUMBER; BEGIN AA := :NUMBER_OF_EMP; SELECT COUNT(EMPNO) INTO C FROM EMP; OPEN S; FOR A IN 1..AA LOOP FETCH S INTO NAME, SALARY; DBMS_OUTPUT.
How many types of cursors are there?
There are three more types of Forward Only Cursors. Forward_Only KEYSET, FORWARD_ONLY STATIC and FAST_FORWARD. A FORWARD_ONLY STATIC Cursor is populated at the time of creation and cached the data to the cursor lifetime. It is not sensitive to any changes to the data source.
Why do we use cursor in SQL?
In SQL procedures, a cursor make it possible to define a result set (a set of data rows) and perform complex logic on a row by row basis. By using the same mechanics, an SQL procedure can also define a result set and return it directly to the caller of the SQL procedure or to a client application.
What are different types of cursors in Oracle?
The cursor is of two types.
- Implicit Cursor.
- Explicit Cursor.
Can we use cursor inside another cursor?
The trick to declaring a cursor within a cursor is that you need to continue to open and close the second cursor each time a new record is retrieved from the first cursor. That way, the second cursor will use the new variable values from the first cursor.
Why cursors are used in PL SQL?
The major function of a cursor is to retrieve data, one row at a time, from a result set, unlike the SQL commands which operate on all the rows in the result set at one time. Cursors are used when the user needs to update records in a singleton fashion or in a row by row manner, in a database table.
Why cursor is used in PL SQL?
What are the three advantages of cursors?
Advantages
- Cursors can be faster than a while loop but they do have more overhead.
- It is we can do RowWise validation or in other way you can perform operation on each Row. It is a Data Type which is used to define multi-value variable.
- Cursors can be faster than a while loop but at the cost of more overhead.
Can you nest cursors?
You can nest cursors no problem as long as you eventually break out of your loop.
How do I pass a value from one cursor to another cursor in PL SQL?
It is possible to reference another cursor within the first one: declare cursor c1 is select distinct Assigned from table_name; cursor c2(p_Assigned in varchar2) is select id, Assigned from table_name where Assigned = p_Assigned; begin for r1 in c1 loop dbms_output.
How many types of cursor are there?
There are 2 types of Cursors: Implicit Cursors, and Explicit Cursors. These are explained as following below. Implicit Cursors: Implicit Cursors are also known as Default Cursors of SQL SERVER.
Declare Cursor: A cursor is declared by defining the SQL statement that returns a result set.
How do you create a cursor in SQL?
– Most Common SQL Server Cursor Syntax – SQL Server Cursor as a Variable – SQL Server Cursor as Output of a Stored Procedure – SQL Server Cursor Current Of Example – SQL Server Cursor Alternative with a WHILE Loop
How to create cursor in SQL Server with example?
We have first declared three variables that will hold data from the cursor temporarily.
How to declare a SQL cursor?
DECLARE@id INT,@c_name NVARCHAR (50),@city NVARCHAR (50)