2) A ref cursor is defined at runtime and can be opened dynamically but a regular cursor is static and defined at compile time. 3) A ref cursor can be passed to another PL/SQL routine (function or procedure) or returned to a client. A regular cursor can implicitly fetch 100 rows at a time if used with CURSOR FOR LOOP.

Hereof, what is ref cursor in Oracle with example?

A REF CURSOR is a PL/SQL data type whose value is the memory address of a query work area on the database. In essence, a REF CURSOR is a pointer or a handle to a result set on the database. REF CURSOR s are represented through the OracleRefCursor ODP.NET class.

Subsequently, question is, what is 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 can be opened on the server and passed to the client as a unit rather than fetching one row at a time. Ref Cursors are opened with an OPEN FOR statement.

Hereof, what is SYS ref cursor in Oracle?

SYS_REFCURSOR is a predefined weak ref cursor which means we do not have to define it into our code like we did with the explicit weak ref cursor in the previous tutorial. When using SYS_REFCURSOR, you just have to create a cursor variable and nothing else.

How do you declare a ref cursor?

With a cursor variable, you simply pass the reference to that cursor. To declare a cursor variable, you use the REF CURSOR is the data type. PL/SQL has two forms of REF CURSOR typeS: strong typed and weak typed REF CURSOR .

What is Pragma Autonomous_transaction?

The AUTONOMOUS_TRANSACTION pragma changes the way a subprogram works within a transaction. A subprogram marked with this pragma can do SQL operations and commit or roll back those operations, without committing or rolling back the data in the main transaction. Pragmas are processed at compile time, not at run time.

Why do we use ref cursor in Oracle?

A ref cursor is a pointer to a result set. This is normally used to open a query on the database server, then leave it up to the client to fetch the result it needs. A ref cursor is also a cursor, though normally ther term cursor is used when discussing static SQL.

Do we need to close ref cursor in Oracle?

2) in general Oracle will automatically "deinstantiate" objects when they "GO OUT OF SCOPE". So, when the code that opened the cursor exits, Oracle will close the cursor for you if you forget to do it. This rule applies to several kinds of objects when Oracle is executing your code.

Is ref cursor return Oracle?

REF CURSOR is the Oracle data type for a cursor variable. Because JDBC does not support a cursor variable data type, the Oracle driver returns REF CURSOR output parameters and return values to the application as result sets.

What is strong ref cursor in Oracle?

A ref cursor which has fixed return type is called a Strong Ref Cursor in Oracle Database. Because of fixed return type, strong ref cursors can only be used selectively. For instance with those SELECT statements that return the result whose datatype matches with the one that you have fixed during cursor's declaration.

What is bulk collect in Oracle?

A bulk collect is a method of fetching data where the PL/SQL engine tells the SQL engine to collect many rows at once and place them in a collection. The SQL engine retrieves all the rows and loads them into the collection and switches back to the PL/SQL engine. All the rows are retrieved with only 2 context switches.

What is ref in SQL?

Definition: In Oracle PL/SQL, REF data types are pointers that uniquely identify a piece of data as an object. Note that a NULL object reference is different from a Dangling Reference. To insert data into a ref column, the REF function is used to get an object instance reference.

Is it good to use limit keyword with bulk collect?

No, we cannot use the LIMIT clause with SELECT-INTO statement. So always remember the LIMIT clause can only be used when you are using BULK COLLECT with FETCH-INTO statement. It cannot be used when you are using bulk collect with SELECT-INTO statement.

What is the difference between ref cursor and Sys_refcursor?

There is no difference between using a type declared as REF CURSOR and using SYS_REFCURSOR , because SYS_REFCURSOR is defined in the STANDARD package as a REF CURSOR in the same way that we declared the type ref_cursor . type sys_refcursor is ref cursor; SYS_REFCURSOR was introduced in Oracle 9i.

What is Oracle collection?

A Collection is an ordered group of elements of particular data types. Collections are most useful things when a large data of the same type need to be processed or manipulated. Collections can be populated and manipulated as whole using 'BULK' option in Oracle.

What is bulk collect in Oracle with example?

What is BULK COLLECT? BULK COLLECT reduces context switches between SQL and PL/SQL engine and allows SQL engine to fetch the records at once. Oracle PL/SQL provides the functionality of fetching the records in bulk rather than fetching one-by-one.

Can ref cursor be used with procedure out parameter?

Using Ref Cursors. The example below uses a ref cursor to return a subset of the records in the EMP table. The following procedure opens a query using a SYS_REFCURSOR output parameter. The cursor can also be referenced as a Java ResultSet.

How do I run a stored procedure in Oracle SQL Developer?

how to Execute Stored Procedure in SQL Developer?
  1. Open SQL Developer and connect to the Oracle Database.
  2. Then left side in Connections pane, expand the schema node in which you want to execute the stored procedure.
  3. Then expand the Procedures node and select the stored procedure you want to execute and do the right click on it.

What is Sys_refcursor in PL SQL?

SYS_REFCURSOR is a REF CURSOR type that allows any result set to be associated with it. This is known as a weakly-typed REF CURSOR. Only the declaration of SYS_REFCURSOR and user-defined REF CURSOR variables are different.

What is a cursor variable?

Cursor variables (PL/SQL) A cursor variable is a cursor that contains a pointer to a query result set. The result set is determined by execution of the OPEN FOR statement using the cursor variable. The same cursor variable can be opened a number of times with separate OPEN FOR statements containing different queries.

Can we use Isopen attribute with implicit cursor?

An implicit cursor has attributes that return information about the most recently run SELECT or DML statement that is not associated with a named cursor. Note: You can use cursor attributes only in procedural statements, not in SQL statements. SQL%ISOPEN always has the value FALSE .

What is mutating error in Oracle?

A mutating table error (ORA-04091) occurs when a row-level trigger tries to examine or change a table that is already undergoing change (via an INSERT, UPDATE, or DELETE statement). In particular, this error occurs when a row-level trigger attempts to read or write the table from which the trigger was fired.