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Resync Command Property-Dynamic (ADO)

  • Článok

Specifies a user-supplied command string that the Resync method issues to refresh the data in the table named in the Unique Table dynamic property.

Settings and Return Values

Sets or returns a String value which is a command string.

Remarks

The Recordset object is the result of a JOIN operation executed on multiple base tables. The rows affected depend on the AffectRecords parameter of the Resync method. The standard Resync method is executed if the Unique Table and Resync Command properties are not set.

The command string of the Resync Command property is a parameterized command or stored procedure that uniquely identifies the row being refreshed, and returns a single row containing the same number and order of columns as the row to be refreshed. The command string contains a parameter for each primary key column in the Unique Table; otherwise, a run-time error is returned. The parameters are automatically filled in with primary key values from the row to be refreshed.

Here are two examples based on SQL:

1) The Recordset is defined by a command:

SELECT * FROM Customers JOIN Orders ON   
   Customers.CustomerID = Orders.CustomerID  
   WHERE city = 'Seattle'  
   ORDER BY CustomerID

The Resync Command property is set to:

"SELECT * FROM   
   (SELECT * FROM Customers JOIN Orders   
   ON Customers.CustomerID = Orders.CustomerID  
   city = 'Seattle' ORDER BY CustomerID)  
WHERE Orders.OrderID = ?"

The Unique Table is Orders and its primary key, OrderID, is parameterized. The sub-select provides a simple way to programmatically ensure that the same number and order of columns are returned as by the original command.

2) The Recordset is defined by a stored procedure:

CREATE PROC Custorders @CustomerID char(5) AS   
SELECT * FROM Customers JOIN Orders ON   
Customers.CustomerID = Orders.CustomerID   
WHERE Customers.CustomerID = @CustomerID

The Resync method should execute the following stored procedure:

CREATE PROC CustordersResync @ordid int AS   
SELECT * FROM Customers JOIN Orders ON   
Customers.CustomerID = Orders.CustomerID  
WHERE Orders.ordid  = @ordid

The Resync Command property is set to:

"{call CustordersResync (?)}"

Once again, the Unique Table is Orders and its primary key, OrderID, is parameterized.

Resync Command is a dynamic property appended to the Recordset object Properties collection when the CursorLocation property is set to adUseClient.

Applies To

Recordset Object (ADO)