What is multi row fetch in DB2?
What is multi row fetch in DB2?
The multiple-row FETCH statement can be used to retrieve multiple rows from a table or view with a single FETCH statement. The multiple-row FETCH statement can be used with both serial and scrollable cursors. The operations used to define, open, and close a cursor for a multiple-row FETCH remain the same.
Is multirow fetching?
Multi row fetch is one of the most powerful features of DB2 V8, which can give significant performance improvements to of your DB2 application. So what is multi row fetch or MRF , as the name suggests it simply mean fetching multiple rows at a time using your cursor.
What is Rowset in DB2?
ROWSET processing is a group of rows for the result set of a query that are returned by a single FETCH statement. You can control the number of rows you want to fetch and return by specifying rowset limit in your program.
What is scrollable cursor in DB2?
A scrollable cursor is cursor that can be moved in both a forward and a backward direction. Scrollable cursors can be either row-positioned or rowset-positioned.
Where do we declare cursor in Cobol?
DECLARE CURSOR can be coded in DATA DIVISION and PROCEDURE DIVISION. The SQL SELECT statement that required in retrieving the data from table(s) will be declared in DECLARE CURSOR. DECLARE CURSOR may have GROUP BY, ORDER BY in it.
What is null indicator in DB2?
The null indicator is used by DB2 to track whether its associated column is null or not. A positive value or a value of 0 means the column is not null and any actual value stored in the column is valid. A negative value indicates that the column is set to null.
What is the use of Sqlerrd 3?
For SQLCODES -911 and -913, SQLERRD(3) contains the reason code for the timeout or deadlock. When an error is encountered in parsing a dynamic statement, or when parsing, binding, or executing a native SQL procedure, SQLERRD(3) will contain the line number where the error was encountered.
How does cursor work in Db2?
Db2 has a mechanism called a cursor . In Db2, an application program uses a cursor to point to one or more rows in a set of rows that are retrieved from a table. You can also use a cursor to retrieve rows from a result set that is returned by a stored procedure.
What is cursor and types of cursor?
Cursor is a Temporary Memory or Temporary Work Station. It is Allocated by Database Server at the Time of Performing DML operations on Table by User. Cursors are used to store Database Tables. There are 2 types of Cursors: Implicit Cursors, and Explicit Cursors.
What is cursor life cycle?
SQL Cursor Life Cycle A cursor is opened for storing data retrieved from the result set. Fetching Cursor. When a cursor is opened, rows can be fetched from the cursor one by one or in a block to do data manipulation. Closing Cursor. The cursor should be closed explicitly after data manipulation.
Why cursors are used in DB2?
In Db2, an application program uses a cursor to point to one or more rows in a set of rows that are retrieved from a table. You can also use a cursor to retrieve rows from a result set that is returned by a stored procedure. Your application program can use a cursor to retrieve rows from a table.
What is importance of null indicator?
A galvanometer or other device that indicates when voltage or current is zero; used chiefly to determine when a bridge circuit is in balance. Also known as null detector.
How to fetch more rows using multiple row fetch?
Line 3 and 4: This is the data structure array. When I perform the multiple row fetch I will be moving the rows into here. By using the EXTNAME the compiler defines the data structure’s subfields to be the same as the file’s fields.
What happens if fetch prior is the first fetch?
If FETCH PRIOR is the first fetch against a cursor, no row is returned and the cursor is left positioned before the first row. Returns the first row in the cursor and makes it the current row. Returns the last row in the cursor and makes it the current row.
How does fetch work in Transact SQL Server?
FETCH (Transact-SQL) Retrieves a specific row from a Transact-SQL server cursor. Syntax. Arguments. Returns the result row immediately following the current row and increments the current row to the row returned. If FETCH NEXT is the first fetch against a cursor, it returns the first row in the result set.
Where does the cursor go in the fetch function?
After the fetch operation, the cursor is positioned on the last row fetched. For example, FETCH PRIOR FROM C1 FOR 3 ROWS causes the previous row, the current row, and the next row to be returned, in that order. The cursor is positioned on the next row. FETCH RELATIVE -1 FROM C1 FOR 3 ROWS returns the same result.
