Quick Answer: What Are Ref Cursors In Oracle?

How do I run a cursor?

There are four steps in using an Explicit Cursor.DECLARE the cursor in the Declaration section.OPEN the cursor in the Execution Section.FETCH the data from the cursor into PL/SQL variables or records in the Execution Section.CLOSE the cursor in the Execution Section before you end the PL/SQL Block..

What is SYS ref cursor?

SYS_REFCURSOR is a REF CURSOR type that allows any result set to be associated with it. This is known as a weakly-typed REF CURSOR. Only the declaration of SYS_REFCURSOR and user-defined REF CURSOR variables are different.

How do I run a cursor in SQL Developer?

To open a cursor, you use the following syntax: OPEN cursor_name; In this syntax, the cursor_name is the name of the cursor declared in the declaration section. When you open a cursor, Oracle parses the query, binds variables, and executes the associated SQL statement.

What is cursor and its types?

Cursor is a Temporary Memory or Temporary Work Station. It is Allocated by Database Server at the Time of Performing DML operations on Table by User. Cursors are used to store Database Tables. There are 2 types of Cursors: Implicit Cursors, and Explicit Cursors.

What are cursors in SQL?

A cursor holds the rows (one or more) returned by a SQL statement. The set of rows the cursor holds is referred to as the active set. You can name a cursor so that it could be referred to in a program to fetch and process the rows returned by the SQL statement, one at a time.

Can we declare cursor inside begin?

You can declare multiple cursors in the same pl/sql block. There is no need to declare the second cursor after you’ve opened the first cursor! Looking at that, you’ve got a nested cursor loop. … If you’re wanting to write the results of the sql query out as a file, you’ll need to use UTL_FILE , instead of DBMS_OUTPUT .

Can we use two cursors in a procedure?

Standard cursor in MySQL allow only one HANDLER. However, when we use multiple cursors like a nested loop, the handler will stop both cursors at the same time. Since we cannot declare two handlers for each cursor, we need to use BLOCK. Below is the example of MySQL’s stored procedure using multiple cursors.

Can we pass parameters to cursor in Oracle?

We can pass parameters into a cursor and use them in the query. We can only pass values to the cursor; and cannot pass values out of the cursor through parameters. Only the datatype of the parameter is defined, not its length.

What is the difference between cursor and ref cursor in Oracle?

2 Answers. 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.

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

When you open and execute your function, SQL Developer automatically adds some code to the ANON block that allows us to grab the refcursor coming back from the database and assign it to a grid in SQL Developer. DECLARE v_Return SYS_REFCURSOR; BEGIN v_Return := REFCURSOR_FUNCTION(); /* Legacy output: DBMS_OUTPUT.

What are the different types of cursor?

SQL Server Different Types of CursorsStatic Cursors. A static cursor populates the result set at the time of cursor creation and the query result is cached for the lifetime of the cursor. … Dynamic Cursors. … Forward Only Cursors. … Keyset Driven Cursors.

What is ref cursor example?

The following shows an example of a strong REF CURSOR . DECLARE TYPE customer_t IS REF CURSOR RETURN customers%ROWTYPE; c_customer customer_t; This form of cursor variable called strong typed REF CURSOR because the cursor variable is always associated with a specific record structure, or type.

What is strong ref cursor in Oracle?

A ref cursor which has fixed return type is called a Strong Ref Cursor in Oracle Database. Because of fixed return type, strong ref cursors can only be used selectively. For instance with those SELECT statements that return the result whose datatype matches with the one that you have fixed during cursor’s declaration.

What is a cursor Oracle?

A Cursor is a pointer to this context area. Oracle creates context area for processing an SQL statement which contains all information about the statement. PL/SQL allows the programmer to control the context area through the cursor. A cursor holds the rows returned by the SQL statement.

Is ref cursor in Oracle?

Using REF CURSOR s is one of the most powerful, flexible, and scalable ways to return query results from an Oracle Database to a client application. A REF CURSOR is a PL/SQL data type whose value is the memory address of a query work area on the database. … A REF CURSOR refers to a memory address on the database.

How do I pass one cursor to 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.

How do I execute a stored procedure with ref cursor in SQL Developer?

6 Answers. create or replace procedure my_proc( p_rc OUT SYS_REFCURSOR ) as begin open p_rc for select 1 col1 from dual; end; / variable rc refcursor; exec my_proc( :rc ); print rc; will work in SQL*Plus or SQL Developer.