Close: This is an exit part of the cursor and used to close a cursor. Deallocate: In this part, we delete the cursor definition and release all the system resources associated with the cursor. A static cursor can move forward and backward. It is identical to the static except that you can only scroll forward. If another user deletes a record, it is inaccessible from our recordset. When a row or column is exclusively locked, other users are not permitted to access the locked data until the lock is released.
It is used for data integrity. This ensures that two users cannot simultaneously update the same column in a row. It specifies that the cursor will lock the rows as they are read into the cursor to ensure that updates or deletes made using the cursor will succeed.
So, the updates or deletes made using the cursor will not succeed if the row has been updated outside the cursor. The statement has been terminated. When executing this cursor, we will get an error because the static cursor does not allow modifications in data.
Cursors are used when the user needs to update records in a singleton fashion or in a row by row manner, in a database table. Microsoft SQL Server supports the following 4 types of cursors. A static cursor populates the result set during cursor creation and the query result is cached for the lifetime of the cursor. This is the default type of cursor. How many types of cursors are there? What is the cursor? In an operating system with a graphical user interface GUI , the cursor is also a visible and moving pointer that the user controls with a mouse, touch pad, or similar input device.
What is the cursor in DBMS? This temporary work area is used to store the data retrieved from the database, and manipulate this data. What are implicit cursors?
Implicit cursors are automatically created by Oracle whenever an SQL statement is executed, when there is no explicit cursor for the statement.
What is cursor in database with example? In computer science, a database cursor is a control structure that enables traversal over the records in a database. Cursors facilitate subsequent processing in conjunction with the traversal, such as retrieval, addition and removal of database records.
A cursor can be viewed as a pointer to one row in a set of rows. You should avoid the use of the cursor. We should use cursor in that case when there is no option except cursor. Types of Cursors Static Cursors A static cursor populates the result set at the time of cursor creation and the query result is cached for the lifetime of the cursor. A static cursor can move forward and backward direction. A static cursor is slower and use more memory in comparison to other cursor. Hence you should use it only if scrolling is required and other types of cursors are not suitable.
By default static cursors are scrollable. SQL Server static cursors are always read-only. Dynamic Cursors A dynamic cursor allows you to see the data updation, deletion and insertion in the data source while the cursor is open.
Hence a dynamic cursor is sensitive to any changes to the data source and supports update, delete operations. By default dynamic cursors are scrollable. Forward Only Cursors A forward only cursor is the fastest cursor among the all cursors but it doesn't support backward scrolling. You can update, delete data using Forward Only cursor.
It is sensitive to any changes to the original data source. There are three more types of Forward Only Cursors.
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