What is reference cursor in PL SQL?

What is reference cursor in PL SQL?

A REF CURSOR is a PL/SQL data type whose value is the memory address of a query work area on the database. In essence, a REF CURSOR is a pointer or a handle to a result set on the database.

How do I display ref cursor output in PL SQL Developer?

Using the PRINT command in a SQL Worksheet Using the classic SQL*PLUS PRINT command to view the refcursor output will work in SQL Developer just like it would work in your command line tools. You execute your program, you create a local variable or 3 to ‘catch’ said output, and then you PRINT it.

What is an implicit cursor FOR LOOP statement?

The cursor FOR LOOP statement implicitly declares its loop index as a record variable of the row type that a specified cursor returns, and then opens a cursor. With each iteration, the cursor FOR LOOP statement fetches a row from the result set into the record.

Does PL SQL allow forward references?

PL/SQL does not allow forward references. You must declare an item before referencing it in any other statements. Also, you must declare subprograms at the end of a declarative section after all other program items.

What is the difference between cursor and ref cursor?

A cursor is really any SQL statement that runs DML (select, insert, update, delete) on your database. A ref cursor is a pointer to a result set. This is normally used to open a query on the database server, then leave it up to the client to fetch the result it needs.

What is the difference between ref CURSOR and Sys_refcursor?

There is no difference between using a type declared as REF CURSOR and using SYS_REFCURSOR , because SYS_REFCURSOR is defined in the STANDARD package as a REF CURSOR in the same way that we declared the type ref_cursor . type sys_refcursor is ref cursor; SYS_REFCURSOR was introduced in Oracle 9i.

How do I execute a CURSOR in Oracle SQL Developer?

There are four steps in using an Explicit Cursor.

1. DECLARE the cursor in the Declaration section.
2. OPEN the cursor in the Execution Section.
3. FETCH the data from the cursor into PL/SQL variables or records in the Execution Section.
4. CLOSE the cursor in the Execution Section before you end the PL/SQL Block.

What is implicit cursor in PL SQL?

Implicit cursors are automatically created by Oracle whenever an SQL statement is executed, when there is no explicit cursor for the statement. For INSERT operations, the cursor holds the data that needs to be inserted. For UPDATE and DELETE operations, the cursor identifies the rows that would be affected.

What are the cursor attributes used in PL SQL?

Each cursor has a set of attributes that enables an application program to test the state of the cursor. These attributes are %ISOPEN, %FOUND, %NOTFOUND, and %ROWCOUNT. This attribute is used to determine whether a cursor is in the open state.

What is implicit cursor in Oracle PL SQL?

Implicit cursors are automatically created by Oracle whenever an SQL statement is executed, when there is no explicit cursor for the statement. Whenever a DML statement (INSERT, UPDATE and DELETE) is issued, an implicit cursor is associated with this statement.

Which of the following is true about cursor in PL SQL?

Q 24 – Which of the following is true about PL/SQL cursors? A – Explicit cursors are automatically created by Oracle. B – Implicit cursors are programmer defined cursors. C – The most recent implicit cursor is called the SQL cursor, and has the attributes like %FOUND, %ISOPEN, %NOTFOUND, and %ROWCOUNT.

What is a strong REF CURSOR in PL / SQL?

There are two types of Ref Cursors in PL/SQL. These are: What is Strong Ref Cursor in Oracle Database? Any Ref Cursor which has a fixed return type is called a Strong Ref Cursor. Moreover such ref cursors can only be used with some SELECT statements.

How is a cursor variable declared in PL / SQL?

With a cursor variable, you simply pass the reference to that cursor. To declare a cursor variable, you use the REF CURSOR is the data type. PL/SQL has two forms of REF CURSOR typeS: strong typed and weak typed REF CURSOR.

How to declare ref cursors in Oracle Database?

Here is the generalized syntax for declaring Ref cursors in Oracle Database: DECLARE TYPE [cursor_variable_name] IS REF CURSOR [RETURN (return_type)]; Syntax can be modified and used depending on what type of Ref Cursors you want to use in your application.

What happens when you open a cursor in SQL?

When you open a cursor, Oracle parses the query, binds variables, and executes the associated SQL statement. Oracle also determines an execution plan, associates host variables and cursor parameters with the placeholders in the SQL statement, determines the result set, and sets the cursor to the first row in the result set.