A ref cursor can be opened on the server and passed to the client as a unit rather than fetching one row at a time. May 10, 2016 89 videos play all plsql tutorial for beginners by manish sharma rebellionrider manish sharma oracle pl sql interview question explain parameterized cursor and for cursor duration. Stack overflow for teams is a private, secure spot for you and your coworkers to find and share information. Here is an example script that performs dynamic sql and returns the data as a ref cursor.
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. Cursor attributes reveal the cursor related information and status. An explicit cursor may accept a list of parameters. This needs to be done using only sql and via a sql join, exists or in operation. The ref cursor is a data type in the oracle plsql language. Building a report with multibyte characters for pdf output. The cursor variable is specified as an in out parameter so that the result set is made available to the caller of the procedure. In this tutorial, you will learn how to use mysql cursor in stored procedures to iterate through a result set. As other answers pointed out they are memory structures used to temporarily store and iterate through a query result set in plsql. Once the processing is complete we can use a ref cursor to pass the recordset out to an application. Cursor expressions as arguments to functions called from sql.
After creating package specs that define the ref cursors, you are ready to define the queries, as described in this section to create a ref cursor query. Plsql cursor by practical examples oracle tutorial. This section discusses the following aspects of using the ref cursor data type and oraclerefcursor objects. Oracle apps technical interview questions and answers pdf. Run operations using ref cursors in oracle database using the. One can use a ref cursor as target of an assignment, and it can be passed as parameter to other program units. Apr 26, 2016 89 videos play all plsql tutorial for beginners by manish sharma rebellionrider manish sharma sql server programming part 12 cursors duration. Plsql allows the programmer to control the context area through the cursor.
Ref cursors may be dynamically opened or opened based on logic. It declares a weak ref cursor and that too without declaring the ref pointer type. A cursor holds the rows returned by the sql statement. Returning a ref cursor from a oracle function stack overflow. In this chapter, we will discuss the cursors in plsql. In essence, a ref cursor is a pointer or a handle to a result set on the database. Return values from a plsql table into a ref cursor. A ref cursor is a plsql data type whose value is the memory address of a query work area on the database. Cursor cursor is one of the fundamental feature of oracle. Ref cursor in pl sql pdf tutorial with examples for more information, see using cursor variables ref cursors. In the object navigator, doubleclick the view icon next to the data model node to display the data model view in the data model view, click the ref cursor query tool in the tool palette. For example, a select statement that includes an identifier that is unknown at. All of yours tutorial is really really really very informative. Net framework data provider for oracle supports the oracle ref cursor data type.
A ref cursor is an oracle plsql data type that represents a pointer to a result set in the oracle database. Learn more visual basic with oracle 11g using ref cursor not working. For additional information about dynamic sql, see oracle database application. This tutorial introduces you to plsql cursor variables and how to manage cursors variables using ref cursor.
Oracle raises an exception if select returns no rows or more than one row. A ref cursor is a datatype that holds a cursor value in the same way that a varchar2 variable will hold a string value. We can allocate different storage locations to the cursor when the program runs. Oracle creates context area for processing an sql statement which contains all information about the statement. Thats it for this tutorial on the introduction to plsql ref cursors in oracle database.
This is a powerful capability in that the cursor can. Each time you open the cursor, you can pass different arguments to the cursor, which results in different result sets. Only thing which is physically available and visible to them is the cursor status flags and information. When using the data provider to work with oracle ref cursors, you should consider the following behaviors. Oracle creates a memory area, known as the context area, for processing an sql statement, which contains all the information needed for processing the statement. To create a ref cursor query, you first create a package spec that defines the ref cursor. It represents a cursor or a result set in oracle database. Oracle database plsql users guide and reference oracle docs. The ref cursor can be assigned to other ref cursor variables.
First we create a temporary table to hold the data during the processing. A cursor is a pointer that points to a result of a query. A normal plsql cursor pdf fillable form per page is static in definition. Sql server cursor explained by examples sql server tutorial. Dec 20, 2016 i hope before knowing about ref cursors you would have a fair idea of what cursors in general are. Different from implicit and explicit cursors, a cursor variable is not tied to any specific query. The set of rows the cursor holds is referred as active set.
Returning a ref cursor from a procedure plsql this example demonstrates how to define and open a ref cursor variable, and then pass it as a procedure parameter. Run operations using ref cursors in oracle database using the wcf service model. Doing a cursor loop fetch and inside doing another cursor loop fetch, is called a nested loop join and sql is significantly better and faster at. Whenever oracle executes an sql statement such as select into, insert, update, and delete, it automatically creates an implicit cursor.
Using ref cursor s is one of the most powerful, flexible, and scalable ways to return query results from an oracle database. Inside a plsql program, the result of a select must go somewhere. Apr 26, 2020 a cursor is a pointer to this context area. A ref cursor is a variable, defined as a cursor type, which will point to, or reference a cursor result. Introduction to plsql ref cursors in oracle database. Dynamic sql with ref cursor burleson oracle consulting. Actually, we have ref cursor as an out variable in the plsql procedure, hence trying to use it dynamically inside the cursor for loop conceptually wrong.
They can be used in java by executing a call through a callable statement to the stored procedure and casting the returned ref. Plsql cursors we can manipulate the information within a sql statement by means of assigning a name to a select statement, this concept is known a cursor. Jun 23, 2011 for implicit cursor, the complete execution cycle is internally handled and maintained by the oracle server. Using ref cursors 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 plsql data type whose value is the memory address of a query work area on the database. Using ref cursors is one of the most powerful, flexible, and scalable ways to return query results from an oracle database to a client application. Introduction to oracle 11g cursors eye on databases. Oracle ref cursors allow you to define queries as stored procedures in the database. Meaning that a cursor variable can be opened for any query. Now, let s move onto the package bodies for the implementation. Plsql cursor variables with ref cursor oracle tutorial. This tutorial provides an indepth knowledge on the following items such as oracle tutorial, sql tutorial, sql, pl sql tutorial, oracle, pl sql, mysql tutorial, sql tutorial for beginners, learn sql, oracle database tutorial, sql query tutorial, oracle dba tutorial, plsql tutorial, oracle tutorial pdf, oracle pl sql tutorial, oracle sql tutorial, sql tutorial point, oracle.
Typically the ref cursor definition and the open for. The ref cursor xe ref cursor can be assigned to other ref cursor variables. For developers, implicit cursor appears to be an abstract concept. Plsql ref cursor and oraclerefcursor oracle help center. The ref cursor interface, on the other hand, simply takes as input the owner to search for and returns a single ref cursor that can select as many columns as you like. However, sometimes, you may want to process a data set on a row by row basis. Oracle holds all relevant information about sql and variables in the context area. A cursor variable is a variable that references to a cursor. For example, the following plsql block opens five cursor variables in a single. The microsoft biztalk adapter for oracle database supports ref cursor parameters in procedures, functions. Oracle cursor oracle tutorial sql tutorial wikitechy. Mostly it is used as a generic cursor which can be passed as an argument to a stored sub program. Cursor can be attached to only one query while ref cursor can be used to associate multiple queries at run time. This example demonstrates how to define and open a ref cursor variable, and then pass it as a procedure parameter.
781 695 288 1342 1335 288 1296 747 448 352 606 943 933 845 1021 870 430 554 609 664 1351 362 238 1507 1500 1423 1226 1422 257 1239 425 974 1171 1108 1340 1474 328 79 1279 530 874 1211 916 540