Declare ref cursor in oracle 11g download

Here is the syntax for declaring an updatable cursor. Oracle holds all relevant information about sql and variables in the context area. You cannot store the value of a cursor variable in a collection or database column. Different from implicit and explicit cursors, a cursor variable is not tied to any specific query. Cursor variables have several advantages over explicit cursors including. Can you show an example of a ref cursor with dynamic sql. There is no need for a user defined type unless defining strong type ref cursors the usage of which is debatable in plsql. We are free to use this ref cursor type as parameters for our subroutines and return type for the functions without needing to create them in a package specification, as it is already done by oracle for us. Introduction to plsql ref cursors in oracle database.

Now, you should know how to use a plsql cursor with parameters to fetch data from the database tables. Oracle provides the for update clause of the select statement in an updatable cursor to perform this kind of locking mechanism. Plsql concepts validated up to oracle 11g release 1. You can use %type to provide the data type of a record variable. Cursor variables based on strong and weak ref cursor types create or.

For information on the ref function, see oracle database sql language reference. Strong ref cursors with table based record datatype. You cant open and close it but then fetch from it in an implicit cursor loop. A cursor variable is a pointer that distinguishes the current row in a resultset from a multirow query. For example, you can declare a cursor variable in a plsql host environment such as an oci or proc program, then pass it as an input host variable bind variable to plsql.

Creating a plsql stored procedure that uses ref cursors. Using cursor variables ref cursors what are cursor variables ref cursors. Implicit cursors, based on number of rows affected by the cursors, can be categorized as single row implicit cursors and multiple row implicit cursors. Create sql baseline from cursor cache in oracle dbaclass. Once you define a ref cursor type, you can declare cursor variables of that type. For can be replaced by is for oracle compatibility.

A ref cursor that specifies a specific return type. Limitations of ref cursor variable oracle community. Oracle advanced plsql professional guide focuses on advanced features of oracle. 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. Here is an example script that performs dynamic sql and returns the data as a ref cursor. An explicit cursor is a select statement that is declared in the declare section of a program. This article demonstrates a few simple ways to display the contents of ref cursors. As such it went into a loop, fetching each row of data from the database, using the ref cursor as its reference pointer to the relevant query, and displaying each row of data until it had no more rows to fetch. A ref cursor which has fixed return type is called a strong ref cursor in oracle database. Every cursor variable must be opened with an associated select statement as follows. If you are going to open a cursor, you have to fetch from it in a loop and you have to close it. Using plsql stored procedures and ref cursors oracle docs.

Dynamic sql with ref cursor burleson oracle consulting. Oracle 11g identifies a different categorization basis of implicit cursors. A cursor variable is a variable that references to a cursor. What is the difference between a normal cursor and a ref. We could use any cursor variable, a variable of type ref cursor, or output parameter from a. Meaning that a cursor variable can be opened for any query. Cursor cursor is one of the fundamental feature of oracle. You cannot declare a cursor variable in a package specification. Because of fixed return type, strong ref cursors can only be used selectively. As we learnt in the introduction to the ref cursor that there are three types of plsql ref cursor in oracle database. When a ref cursor is opened, no data is initially returned to the client.

The second one should store all values from an attribute from all the tables which are in the first one. Plsql allows the programmer to control the context area through the cursor. To read more about ref cursor i have created a package to explain few different ref cursor examples. To create a cursor variable, define a ref cursor type, and then declare the cursor variable to be of that type. Declare varchar2 variables of 4000 or more characters. The final output of the procedure should be the list of table names which contains the required codes.

How to get rows value as header with summary information. You can use these free online tutorials as your guide to practice, learn, for training, or reference while programming with pl sql. In essence, a ref cursor is a pointer or a handle to a result set on the database. You associate a select statement with an explicitlydeclared cursor. You cannot use a cursor variable in a cursor for loop statement. The set of rows the cursor holds is referred as active set. Hi, i need to write a procedure which has a cursor that stores the list of table names. In contrast, explicit cursors are tied to individual queries. The easy way to send a ref cursor to plsql with odp. Plsql cursor variables with ref cursor oracle tutorial.

This example demonstrates how to define and open a ref cursor. A ref cursor is a reference to a result set that resides in server memory. Oracle creates context area for processing an sql statement which contains all information about the statement. 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. This book includes scripts and tools to hypercharge oracle 11g performance and you can buy it. Ask tom fetch ref cursor to another ref cursor oracle. Also, in the return clause of a ref cursor type definition, you can use %rowtype to specify a record type that represents a row returned by a strongly not weakly typed cursor variable. It is a plsql datatype using which you can declare a special type of variable called cursor variable. When we opened the cursor, we did not pass any arguments. Defining cursor variables ref cursor return clause. Name of the cursor variable that you are declaring. You do this so that oracle will then prepare your sql statement before running your program. Cursor variables can point to a variety of queries provided the queries have a suitable return type. Developers and dbas get help from oracle experts on.

That is, a package cannot have a public cursor variable a cursor variable that can be referenced from outside the package. Application development tools such as oracle forms, which have a plsql engine, can use cursor variables entirely on the client side. Is it possible to have a plsql procedure that has dynamic sql and uses a ref cursor. There is no need to declare a c1 type for a weakly typed ref cursor. For example, the assignment in example 38 using a ref is not allowed. Get the complete oracle sql tuning information the landmark book advanced oracle sql tuning the definitive reference is filled with valuable information on oracle sql tuning. Ian abramson, michael abbey, michelle malcher, michael corey. Net to create powerful, flexible, and scalable applications. For instance with those select statements that return the result whose datatype matches with the one that you have fixed during cursor s declaration. Sqlplus looked at the ref cursor and saw that it was an open cursor. You cannot define the same cursor more than stead you can only use it. Cursor variables are subject to these restrictions. You cant mix implicit and explicit cursor calls like this. Declaring a cursor variable creates a pointer, not.

For information about strong and weak ref cursor types, see creating cursor variables. Using plsql stored procedures and ref cursors oracle. There are several ways to return query results from an oracle database to a client application, using oracle data provider for. Implicit statement results in oracle database 12c release 1 12. A ref cursor is a variable, defined as a cursor type, which will point to, or reference a cursor result. We need to loop the cursor and for each table name it should look for a code in that particular table. Last issue, i wrote about some new oracle database 11g features, and i continue that coverage in this issue, focusing on my favorite procedural language, plsql.