Ref cursor in oracle pdf

Ask tom difference between cursor and a ref cursor oracle. 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. 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. 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. I have written a function which is returning the ref cursor. Net type for the ref cursor type this section discusses the following aspects of using the ref cursor data type and oraclerefcursor objects. The ref cursor is a data type in the oracle pl sql language. 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. Oracle tutorialonlinetrainingplsqlref cursor part2. Aug 06, 2015 how to test a oracle stored procedure with ref cursor from sqlplus or sql developer.

Ref cursor s are represented through the oraclerefcursor odp. Suggestions, comments, feedbacks and referrals are highly appreciated. Different behavior for ref cursor between oracle 10g and 11g when unique index present. Pl sql ref cursor and oraclerefcursor oracle help center. Different from implicit and explicit cursors, a cursor variable is not tied to any specific query. Oracle database tips by donald burlesonapril 18, 2015. How to convert oracle cursor when migrating to sql server. When declaring the ref cursor in an oracle package, the ref cursor may be strongly bound or it may be weakly bound. Oracle 8i oracle 9i oracle 10g oracle 11g oracle 12c oracle c oracle 18c oracle 19c miscellaneous plsql sql oracle rac oracle apps weblogic linux mysql. Strong plsql ref cursors burleson oracle consulting. A ref cursor is a plsql data type whose value is the memory address of a query work area on the database. Net type for the ref cursor type this section discusses the following aspects of using ref cursor and oraclerefcursor objects obtaining an oraclerefcursor.

For how many years have you been working with physical servers that are starving your database of the memory necessary to deploy important new performance features such as the result cache, memoptimize pool, in memory aggregation, in memory column store, and full database caching. Normally a cursor is a static thing, it points to a query. Net type for the ref cursor type this section discusses the following aspects of using the ref cursor datatype and oraclerefcursor objects obtaining an. It is up to the calling code to manage the cursor once it has been opened. Different behavior for ref cursor between oracle 10g and. Run operations using ref cursors in oracle database using the. For the weak ref cursor the structure does not need to be known at compile time.

This example demonstrates how to define and open a ref cursor variable, and then pass it as a procedure parameter. 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. I tried to call it as a native query, but it didnt work. Archive for the ref cursor tag reference cursors why, when, and how. Oracle tutorialonlinetrainingplsql ref cursor part. So far in this series we have covered the concepts of strong as well as weak ref cursor. Technically, under the covers, at the most basic level, they are the same. Strong ref cursor and weak ref cursor for the strong ref cursor the returning columns with datatype and length need to be known at compile time.

Plsql cursor variables with ref cursor oracle tutorial. When a ref cursor is defined without a return type, it is called as a weakly typed dynamic ref cursor. 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 is a plsql data type that represents a pointer to a serverside result set generated by executing a query. For example, a procedure can open a cursor and use a ref cursor to return a subset of the records to the caller procedure or anonymous plsql block. What is the difference between a normal cursor and a ref. There are two types of cursor variable 1week ref cursor.

However, that said i fail to see why you having to select in one stored procedure, to put the data into a global temporary table and then just join. Hi tom, feels good that i got a chance to ask you a question. The ref cursor xe ref cursor can be assigned to other ref cursor variables. It represents a cursor or a result set in oracle database. Using plsql stored procedures and ref cursors oracle. After many attempts, had to use a collection as input parameter, and fetch. Any ref cursor which has a fixed return type is called a strong ref cursor. The oracle docs specify that the open statement only identifies the result set, but does not retrieve the rows, which happens only with every call to the fetch statement.

Ask tom how to test a function returning a ref cursor. In essence, a ref cursor is a pointer or a handle to a result set on the database. Operations on functions and procedures with ref cursor parameters in oracle database. There is no real difference, in fact, deep down in the data dictionary, we have this definition. For example, an oci client, oracle forms application, and oracle database server can all refer to the same work area. In 10g the cursor will contain the expected results but in 11g the cursor will be empty. New features in plsql for oracle database 10g release 2 10. There are several ways to return query results from an oracle database to a client application, using oracle data provider for.

Using ref cursor in oracle sql developer stack overflow. Operations on functions and procedures with ref cursor. Ref cursors are one of the most powerful, flexible, and scalable methods for returning query results from an oracle database to a client application. I am using oracle sql developer, but i am having an issue seeing results from a package that returns a ref cursor. Net to create powerful, flexible, and scalable applications.

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 variable, defined as a cursor type, which will point to, or reference a cursor result. Although this reduces the chances of runtime errors. This may be a dumb question, but ive never got my head round the strange tablecast. In the previous tutorial we learnt how to create a plsql strong ref cursor using table based record datatype variable.

A cursor variable is a variable that references to a cursor. Run operations using ref cursors in oracle database using the wcf service model. A ref cursor can have an arbitrary query associated with it. It declares a weak ref cursor and that too without declaring the ref pointer type. The oracle ref cursor is a pointer data types that allows you to quickly reference any cursor result usually an internal plsql table array with data values kept in superfast ram. Is there any way to call this function with jpa or hibernate. The ref cursor is a datatype in the oracle plsql language. As other answers pointed out they are memory structures used to temporarily store and iterate through a query result set in plsql. I have a requirement where i should pass cursor variable as input parameter to a procedure and fetch data from that in the procedure. A ref cursor is an oracle plsql data type that represents a pointer to a result set in the oracle database. 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.

Strongly typed the ref cursor type is restricted to an individual return type using the return clause. Until oracle has retrieved all the rows then by definition it does not have an accurate record of how many there are. Sys ref cursor is an oracle built in cursor variable. Basically, the procedure opens a reference cursor, updates a table then completes. A week or two ago, i noticed a discussion on the oracle technical network forum that asked some questions about reference cursors. The name of this context area is same as the cursor name. How cursor variables are defined is the topic of the next section. The fetch statement retrieves rows of data from the result set of a multirow query. We could use any cursor variable, a variable of type ref cursor, or output parameter from a procedure, but the function will make life easy for the examples. One can use a ref cursor as target of an assignment, and it can be passed as parameter to other program units. Using oracle table functions shiby thomas oracle corporation. Jun 27, 2012 i doubt something like this would be feasible. It allows a user to pass this reference to the same cursor among all the programs that need access to the cursor. In addition, the result of select statements datatype should match with the one that was fixed during the strong cursor s declaration.

To handle this situation an exception is raised when no data found. Each ref cursor query is associated with a plsql function that returns a strongly typed ref. This microsoft visual basic example executes a plsql stored procedure that returns a ref cursor parameter, and reads the value as an oracledatareader. Introduction to plsql ref cursors in oracle database. Ref cursor input yref cursor can be used to fetch the input rows. There he asked one question as what is the difference between cursor and ref cursor, and when would you appropriately use each of these. Application development tools such as oracle forms, which have a plsql engine, can use cursor variables entirely on the client side. Mostly it is used as a generic cursor which can be passed as an argument to a stored sub program. The cursor variable is specified as an in out parameter so that the result set is made available to the caller of the procedure. There i demonstrated the use of strong ref cursor to handle the data from all. First, my question is passing ref cursor variables as actual parameters valid in oracle. Meaning that a cursor variable can be opened for any query. You cannot define the same cursor more than stead you can only use it.

The ref cursor can be assigned to other ref cursor variables. There is no dependency on its return structure, thus making it open to all select. As we learnt in the introduction to the ref cursor that there are three types of plsql ref cursor in oracle database strong ref cursor. It represents a cursor or a result set in the oracle database. You can fetch rows one at a time, several at a time, or all at once. Strong ref cursor with user defined record datatype. It doesnt reference a cursor result as there are only results as the data is fetched through the cursor pointer. Net framework data provider for oracle supports the oracle ref cursor data type. Crystal report using ref cursor ole db failed to retrieve. The discussion made me reflect if there were a couple simple rules for using reference cursors. The data is stored in variables or fields that correspond to the columns selected by the query.

Oracle plsql ref cursors ref cursors a ref cursor or cursor variable is just a reference or a handle to a static cursor. Run operations using ref cursors in oracle database using. The ref cursor is a data type in the oracle plsql language. You can open a ref cursor, dynamically or not, and fetch from it within a loop. Declaring the cursor simply means to create one named context area for the select statement that is defined in the declaration part. Different types of cursors in plsql oracle live sql. Moreover such ref cursors can only be used with some select statements. I assume this to mean that open fetches the result set of the query into some memory space in the server probably an area not part of the plsql memory space, after which every. Defining cursor variables ref cursor return clause. Plsql strong ref cursor with user defined record datatype. I have some data in a header table and a bunch of child tables. Plsql ref cursor and oraclerefcursor oracle help center.

Plsql weak ref cursors oracle plsql tips by boobal ganesan. Using cursor variables ref cursors posted by himanshu karki at 7. In apex, i tried the forms on procedure option but was struggling with it. To read more about ref cursor i have created a package to explain few different ref cursor examples. Strong ref cursor and weak ref cursor what is the difference between cursor and ref cursor, and when would you appropriately use each of these. The refcursor declared in this programs scope is never opened as when it is assigned to the same refcursors variable in the out parameter, the information of the cursor variable from the server program is copied into this variable, thus making it its alias.

Thats it for this tutorial on the introduction to plsql ref cursors in oracle database. The documentation team has to enter the date and the changes made on the respective date will be displayed on apex. If so, could anyone help me in sorting out the way. When using the data provider to work with oracle ref cursors, you should consider the following behaviors. Using plsql stored procedures and ref cursors oracle docs.

Oracle 12c introduced implicit statement results, and sqlplus and sqlcl display the contents of implicit statement. Opening the cursor will instruct the plsql to allocate the memory for this cursor. Plsql composite data type collections associative array, varray and nested tables kafka java producer and consumer. But i dont know in this situation how should null cursor be. But in one situation the ref cursor returns no rows selected. Dec 20, 2016 i hope before knowing about ref cursors you would have a fair idea of what cursors in general are. To use these examples, you may need to create the oracle tables, and you must create a plsql package and package body. This example executes a plsql stored procedure that returns two ref cursor parameters, and fills a dataset with the rows that are returned. Ref cursors may be dynamically opened or opened based on logic. A ref cursor being a pointer to an open cursor used to send an open cursor as an out argument to the client app to loop through the record.

6 134 336 1124 1200 654 262 899 741 1138 409 756 1030 1523 1431 279 455 961 1523 857 1146 75 637 1257 207 1451 1034 455 628 401 1150 1063 50 162 481 866 281 513 74 1313 968 1257 296