I cursori solo in avanti non consentono lo scorrimento all'indietro. L'unica opzione di scorrimento disponibile è FETCH NEXT.
Solo avanti I cursori statici sono sensibili a qualsiasi modifica (aggiornamento, eliminazione, inserimento) apportata all'origine dati originale. Se le modifiche vengono apportate, verranno estratte su Next Fetch.
Script per Forward_Only Dynamic Cursor
--drop table dbo.Customer
Create table dbo.Customer (
CustomerId Int Identity(1,1),
CustomerName VARCHAR(100),
StreetAddress VARCHAr(100),
City VARCHAR(100),
State CHAR(2))
go
--Insert couple of Records in Sample Table
Insert into dbo.Customer
Select 'Aamir shahzad','Test Street Address','Charlotte','NC'
Union
Select 'M Raza','Test Street Address','Charlotte','NC'
Select * from dbo.Customer
--Insert NEW Record
Insert into dbo.Customer
Select 'John Smith','Test Street Address','New York City','NY'
--Delete Records
Delete from dbo.Customer
Where CustomerName in ('Aamir Shahzad','M Raza')
--Update All Record
Update dbo.Customer
set CustomerName='NO NAME'
--Cursor Script
Declare @CustomerID INT
Declare @CustomerNAme VARCHAR (100)
DECLARE @StreetAddress VARCHAR(100)
DECLARE @City VARCHAR(100)
DECLARE @State CHAR(2)
--DECLARE A CURSOR
DECLARE CUR CURSOR
Forward_Only Dynamic
FOR
Select CustomerID,CustomerName,StreetAddress,City,State from dbo.Customer
--OPEN CURSOR
OPEN CUR
Print 'CURSOR IS OPEN'
--FETCH NEXT RECORD
FETCH NEXT FROM CUR INTO @CustomerID,@CustomerNAme,@StreetAddress,@City,@State
WHILE @@FETCH_STATUS=0
BEGIN
RAISERROR ('',0,1) WITH NOWAIT
WAITFOR DELAY '00:00:15'
PRINT CONCAT(@CustomerID,' ',@CustomerNAme,' ',@StreetAddress,' ',@City,' ',@State)
FETCH NEXT FROM CUR INTO @CustomerID,@CustomerNAme,@StreetAddress,@City,@State
END
CLOSE CUR
DEALLOCATE CUR Guarda il video per i dettagli di Forward Only Dynamic Cursor in SQL Server
