In other words, a regular cursor can more efficiently retrieve data by using significantly less code. A regular cursor can implicitly array-fetch 100 rows at a time, whereas a ref cursor must use explicit array fetching. The next performance-related advantage of a regular cursor is also an ease-of-use feature. For instance with those SELECT statements that return the result whose datatype matches with the one that you have fixed during cursor’s declaration. Because of fixed return type, strong ref cursors can only be used selectively. What is strong ref cursor in Oracle?Ī ref cursor which has fixed return type is called a Strong Ref Cursor in Oracle Database. These arguments will be substituted by values when the cursor is opened. Then, you put the CURSOR keyword followed by a list of comma-separated arguments ( name datatype ) that defines parameters for the query. … What is ref cursor in PostgreSQL?ĭeclaring cursors PostgreSQL provides you with a special type called REFCURSOR to declare a cursor variable. Is ref cursor can be used for dynamic queries?Īnswer: Here is an example script that performs dynamic SQL and returns the data as a ref cursor. PL/SQL has two forms of REF CURSOR typeS: strong typed and weak typed REF CURSOR. To declare a cursor variable, you use the REF CURSOR is the data type. Different from implicit and explicit cursors, a cursor variable is not tied to any specific query. What is ref cursor and its typeS?Ī cursor variable is a variable that references to a cursor. Cursor data type result set definitions can be defined by providing a row type definition.
The property of being strongly or weakly typed is defined when the data type is created. There are two main types of cursor data types: weakly-typed cursor data types and strongly-typed cursor data types. The REF CURSOR can be assigned to other REF CURSOR variables. The advantage that a ref cursor has over a plain cursor is that is can be passed as a variable to a procedure or a function.
#Ref cursors series
All the examples in this series have been tested only with Oracle 10gĪ REF CURSOR is a PL/SQL datatype that you can use in a query to fetch data. This article introduces you to the REF CURSOR in Oracle PL/SQL. The resulting cursor can be referenced from PL/SQL as follows. The example below uses a ref cursor to return a subset of the records in the EMP table. Before Beginning This Tutorial open Creating a PL/SQL Stored Procedure that Uses REF CURSORs They define a programming interface for the database rather than allowing the client application to interact with database Description of the illustration connect_se.gif.NET Application with Oracle Developer Tools caution regarding dynamic SQL and the preceding examples in particular: whenever you DECLARE l_names SYS_REFCURSOR l_name VARCHAR2 (32767)
#Ref cursors how to
example demonstrating how to use a PL/SQL SYS_REFCURSOR in Oracle Database.Ĭursor management of DML statements is handled by Oracle Database, but. like we did with the explicit weak ref cursor in the previous tutorial. How To Create PL/SQL SYS_REFCURSOR In Oracle Database. of a manager based on the manager id from the employees table in the sample database. This tutorial introduces you to PL/SQL cursor variables and how to manage cursors The following shows an example of a strong REF CURSOR. How To Create PL/SQL Weak Ref Cursor In Oracle Database In the previous tutorial we learnt how to fetch data of different datatypes see an example which will help you in learning how to create PL/SQL weak ref cursors
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