In contrast to strong ref cursors, weak ref cursors are those which do not have any return type. It declares a weak ref cursor and that too without declaring the ref pointer type. Stronglytyped cursor variables of the ref cursor type require a result set. Here is the syntax for declaring an updatable cursor. Oracle creates context area for processing an sql statement which. It represents a cursor or a result set in the oracle database. Different from implicit and explicit cursors, a cursor variable is not tied to any specific query. Oracle is a registered trademark, and oracle store, oracle9i, plsql, proc, and sqlplus are trademarks or. How to create a table using data returned by ref cursor asked by rohan deshmukh on 6152009 8.
But, returning a ref cursor that has 80 cursors, will have as many round trips as returning 80 ref cursors. Hi rahul, best way of handling exception in refcuror is fetch exit method only. A query work area remains accessible as long as any cursor variable points to it, as you pass the value of a cursor variable from one scope to another. Because of fixed return type, strong ref cursors can only be used selectively. Ask tom difference between cursor and a ref cursor oracle. A cursor is a cursor, by any other name and smells just as sweet. Oracle advanced plsql developer professional guide.
Cursor variables advanced oracle plsql developers guide. Oracle database plsql language reference oracle docs. A ref cursor is a reference to a result set that resides in server memory. There he asked one question as what is the difference between cursor and ref cursor, and when would you appropriately use each of these.
Implicit statement results in oracle database 12c release 1 12. There is no dependency on its return structure, thus making it open to all select. We could use any cursor variable, a variable of type ref cursor, or output parameter from a. Cursor variables give you easy access to centralized data retrieval there are two types of cursor variables. When a ref cursor is opened, no data is initially returned to the client. 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. Now, the data from this ref cursor is to be stored in new table based on the structure of cursor returned by this function. Since weak ref cursors do not have any fixed return type thus they are open to all select statements. A ref cursor which has fixed return type is called a strong ref cursor in oracle database. Did you know that packt offers ebook versions of every book published, with pdf and epub. Oracle tutorialonlinetrainingplsqlref cursor part2. 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.
This example demonstrates how to define and open a ref cursor variable, and then pass it as a procedure parameter. Php pdo with oracle, call stored procedure when output. Basically, the procedure opens a reference cursor, updates a table then completes. The following tip is from the outstanding book oracle plsql tuning. Ask tom fetch ref cursor to another ref cursor oracle. When a ref cursor is defined with a return type, it is called as a strongly typed static ref cursor. Ref cursors may be dynamically opened or opened based on logic. In other words, those ref cursors which do not have fixed return type are called weak ref cursors. Plsql weak ref cursors oracle plsql tips by boobal ganesan. Defining cursor variables ref cursor return clause. One can use a ref cursor as target of an assignment, and it can be passed as parameter to other program units. Ref cursors usually make use of cursor expressions to. Technically, under the covers, at the most basic level, they are the same. John, oracle products that are not apex can consume and process a ref cursor very easily apex because of its architecture can not properly process a ref cursor 11g was suppose to help in this issue, but still they would need to make some code changes in apex to support this.
Different behavior for ref cursor between oracle 10g and. A ref cursor is a datatype that holds a cursor value in the same way that a varchar2 variable will hold a string value 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. Are ref cursors supported in apex oracle community. Introduction to plsql ref cursors in oracle database.
Sqlplus looked at the ref cursor and saw that it was an open cursor. Plsql ref cursor and oraclerefcursor oracle help center. Using cursor variables ref cursors posted by himanshu karki at 7. Cursor variables are created by defining a variable of the ref cursor type. A cursor can be nested in an sql statement using the cursor expression. This microsoft visual basic example executes a plsql stored procedure that returns a ref cursor parameter, and reads the value as an oracledatareader. The cursor expressions are made available in plsql from the oracle version 9i and are majorly used for returning a complex parentchild data in the form of cursors in a single query.
Using ref cursors to return recordsets since oracle 7. The easy way to send a ref cursor to plsql with odp. Oracle tutorialonlinetrainingplsql ref cursor part. Plsql cursor variables with ref cursor oracle tutorial. Sys ref cursor is an oracle built in cursor variable. Plsql is oracle s procedural extension to sql, and it is a true 3gl programming language. By strongly typing the cursor variable, you define what the cursor can return. Mostly it is used as a generic cursor which can be passed as an argument to a stored sub program. When you opt to use a weakly typed cursor, you can anchor it to a plsql structure that is a collection of a plsql record structure. A cursor variable is a pointer that distinguishes the current row in a resultset from a multirow query. Is there any examples how to call oracle s stored procedure when the output parameter is a cursor. When a ref cursor is defined without a return type, it is called as a weakly typed dynamic ref cursor. Weak ref cursor what is the difference between cursor and ref cursor, and when would you appropriately use each of these.
A ref cursor is a plsql data type whose value is the memory address of a query work area on the database. It allows a user to pass this reference to the same cursor among all the programs that need access to the cursor. For instance with those select statements that return the result whose datatype matches with the one that you have fixed during cursor s declaration. First, my question is passing ref cursor variables as actual parameters valid in oracle. Reference cursor as input parameter to a procedure i have a requirement where i should pass cursor variable as input parameter to a procedure and fetch data from that in the procedure. Syntax descriptions are provided in this book for various sql, plsql, or other. This is known as an associative array, and commonly called a plsql table by folks who predate the oraclei documentation that oracle would prefer we forget. Strong plsql ref cursors oracle plsql tips by boobal ganesan. Expert secrets for high performance programming by dr. If none or the same string object is passed in again, the cursor will execute that statement again without performing a prepare or rebinding and redefining. In 10g the cursor will contain the expected results but in 11g the cursor will be empty.
A cursor variable is a variable that references to a cursor. I was able to do it using php with adodb and also oci8 extension. This is most effective for algorithms where the same statement is used, but different parameters are bound to it many times. I have some data in a header table and a bunch of child tables.
How to create a table using data returned by ref cursor. Strong ref cursors with table based record datatype. For example, an oci client, oracle forms application, and oracle database server can all refer to the same work area. Its a great solution if you have to convert calls to oracle stored procedure that return collections from classic asp during the o. There is no real difference, in fact, deep down in the data dictionary, we have this definition. For the weak ref cursor the structure does not need to be known at compile time. Strong plsql ref cursors burleson oracle consulting. Ref cursors are one of the most powerful, flexible, and scalable methods for returning query results from an oracle database to a client application. Oracle provides the for update clause of the select statement in an updatable cursor to perform this kind of locking mechanism. This article demonstrates a few simple ways to display the contents of ref cursors. Different behavior for ref cursor between oracle 10g and 11g when unique index present.
However, it seems politically insensitive to use that language even though oracle published it as such. Meaning that a cursor variable can be opened for any query. The ref cursor is a datatype in the oracle plsql language. This is something that would be impossible to do in plsql with a ref cursor in oracle database 10g. It represents a cursor or a result set in oracle database. Although i am getting two build errors concerning my readerparameters cannot be used like a method. A ref cursor or cursor variable is just a reference or a handle to a static cursor. Using plsql stored procedures and ref cursors oracle. Many of the crossreferences from this book to other books have been made. I am using oracle sql developer, but i am having an issue seeing results from a package that returns a ref cursor. Thats it for this tutorial on the introduction to plsql ref cursors in oracle database.
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