What can I use instead of a cursor?
Temporary tables have been in use for a long time and provide an excellent way to replace cursors for large data sets. Just like table variables, temporary tables can hold the result set so that we can perform the necessary operations by processing it with an iterating algorithm such as a ‘while’ loop.
How do you avoid using cursors what to use instead of cursor and in what cases to do so?
krishnaindia2007
- krishnaindia2007. Answered On : May 8th, 2008.
- You can use bulk binding to avoid cursors. It improves performance by minimizing context switches sql and pl/sql. When you are hadling large volume of data then better to use bulk binding.
Does cursor affect performance?
Cursors could be used in some applications for serialized operations as shown in example above, but generally they should be avoided because they bring a negative impact on performance, especially when operating on a large sets of data.
How do you call a cursor?
To use cursors in SQL procedures, you need to do the following:
- Declare a cursor that defines a result set.
- Open the cursor to establish the result set.
- Fetch the data into local variables as needed from the cursor, one row at a time.
- Close the cursor when done.
How can you avoid cursors?
Row operations can take a long time to execute depending upon the type of task being performed on each row. While the cursor is open, a table cannot be accessed or updated by the other users. This makes cursor-based operations extremely. Therefore, cursors can be avoided wherever they can by the set based operations.
Which is faster cursor or loop?
While SQL While loop is quicker than a cursor, reason found that cursor is defined by DECLARE CURSOR. Every emphasis of the loop will be executed inside system memory and consuming required server assets.
Why cursor is bad for performance?
Because cursors take up memory and create locks. What you are really doing is attempting to force set-based technology into non-set based functionality.
What are the disadvantages of a cursor?
What are the disadvantages of cursors?
- Uses more resources because Each time you fetch a row from the cursor, it results in a network roundtrip.
- There are restrictions on the SELECT statements that can be used.
- Because of the round trips, performance and speed is slow.
What are Oracle Procedures?
Oracle Procedures. A procedure is a group of PL/SQL statements that can be called by name. The call specification (sometimes called call spec) specifies a java method or a third-generation language routine so that it can be called from SQL and PL/SQL.
What is procedure in Plsql?
A stored procedure in PL/SQL is nothing but a series of declarative SQL statements which can be stored in the database catalogue. A procedure can be thought of as a function or a method. They can be invoked through triggers, other procedures, or applications on Java, PHP etc.
Are cursors bad?
Then, as you cycle through the cursor, you are making changes to other tables and still keeping all of the memory and locks of the cursor open. All of which has the potential to cause performance issues for other users. So, as a general rule, cursors are frowned upon.
When to use cursor or stored procedure in SP?
If your SP returns multiple records, only the first will be kept. So if you want multiple records, Stored Procedure is not the way to go. If you want a single record, just declare the appropriate number and type of out parameters rather than a cursor, and set the Stored Procedure transformation accordingly.
Is there a way to declare a cursor within a cur?
The trick to declaring a cursor within a cursor is that you need to continue to and close the second cursor each time a new record is retrieved from the first cursor. That way, the second cursor will use the new variable values from the first cursor.
Can you use cursors in a while loop?
Use LOCAL FAST_FORWARD and there are almost zero reasons not to use CURSORs for these kind of loops. It would definitely outperform this WHILE loop. – Martin