Überwachen und Synchronisieren von Daten in datenbankübergreifenden Anwendungen mithilfe eines Triggers
About
This is a very stripped down version of some code that we set up at a previous client site. They had two very different databases on different servers (customer and dialler) that needed to have certain data syncronised in real time.
There were a couple of ways of doing it, replication, or stored procedures linked to a job or triggers, in their example it had to be a job, because we didn't own the source code for one of the databases, however my preferred method would be using triggers with something like this...
SQL
CREATE TABLE Customer(
CustomerID INT IDENTITY(1,1) CONSTRAINT PK_CustomerID PRIMARY KEY,
CustomerName NVARCHAR(100),
CustomerStatus INT
--,Other Customer Data...
)
CREATE TABLE CustomerAudit(
CustomerAuditID INT IDENTITY(1,1) CONSTRAINT PK_CustomerAuditID PRIMARY KEY,
CustomerAuditType NVARCHAR(100),
CustomerAuditDate DATETIME DEFAULT GETDATE(),
CustomerID INT,
CustomerName NVARCHAR(100),
CustomerStatus INT)
CREATE TABLE Dialler(
CustomerID INT CONSTRAINT PK_DiallerCustomerID PRIMARY KEY,
CustomerStatus INT,
CustomerName NVARCHAR(100),
DiallerStatus INT--Other Dialler Records
)
GO
So now we have created some very basic tables that can store customer data. Next we will create some Stored Procedures to handle updating records on the dialler side.
The reason I have done this as stored procedures is to keep the volume of data down (i don't want server 1 sending database records to server 2), it is in effect pinching what would normally be done in a web environment.
SQL
CREATE PROC DiallerUpdate(@CustomerID INT,@CustomerName NVARCHAR(100),@CustomerStatus INT) AS BEGIN
UPDATE Dialler SET CustomerStatus=@CustomerStatus,CustomerName=@CustomerName
WHERE CustomerID=@CustomerID
END
GO
CREATE PROC DiallerInsert(@CustomerID INT,@CustomerName NVARCHAR(100),@CustomerStatus INT) AS BEGIN
INSERT INTO Dialler(CustomerID,CustomerName,CustomerStatus,DiallerStatus)
SELECT @CustomerID,@CustomerName,@CustomerStatus,0
END
GO
CREATE PROC DiallerDelete(@CustomerID INT) AS BEGIN
DELETE FROM Dialler
WHERE CustomerID=@CustomerID
END
GONow we have created these, we can move onto creating a trigger that will handle sending the data and as we are doing it, we can also auditing our records.
SQL
CREATE TRIGGER CustomerInsert ON Customer AFTER INSERT
AS BEGIN
DECLARE @CustomerID INT,@CustomerName NVARCHAR(100),@CustomerStatus INT
--Get Record Details
SELECT @CustomerID=CustomerID,@CustomerName=CustomerName,@CustomerStatus=CustomerStatus FROM inserted
--Add to Audit
INSERT INTO CustomerAudit(CustomerAuditType,CustomerID,CustomerName,CustomerStatus)
SELECT 'Record Created',@CustomerID,@CustomerName,@CustomerStatus
--Call Insert Procedure
EXEC dbo.DiallerInsert@CustomerID,@CustomerName,@CustomerStatus
END
GO
CREATE TRIGGER CustomerUpdate ON Customer AFTER Update
AS BEGIN
DECLARE @CustomerID INT,@CustomerName NVARCHAR(100),@CustomerStatus INT
--Get Record Details
SELECT @CustomerID=CustomerID,@CustomerName=CustomerName,@CustomerStatus=CustomerStatus FROM inserted
--Add to Audit
INSERT INTO CustomerAudit(CustomerAuditType,CustomerID,CustomerName,CustomerStatus)
SELECT 'Record Updated',@CustomerID,@CustomerName,@CustomerStatus
--Call Update Procedure
EXEC dbo.DiallerUpdate@CustomerID,@CustomerName,@CustomerStatus
END
GO
CREATE TRIGGER CustomerDelete ON Customer AFTER DELETE
AS BEGIN
DECLARE @CustomerID INT,@CustomerName NVARCHAR(100),@CustomerStatus INT
--Get Record Details
SELECT @CustomerID=CustomerID,@CustomerName=CustomerName,@CustomerStatus=CustomerStatus FROM deleted
--Add to Audit
INSERT INTO CustomerAudit(CustomerAuditType,CustomerID,CustomerName,CustomerStatus)
SELECT 'Record Deleted',@CustomerID,@CustomerName,@CustomerStatus
--Call Delete Procedure
EXEC dbo.DiallerDelete@CustomerID
END
GOAnd that is pretty much it, we now have an audit of data, and the records on both sides will be syncrised within milliseconds... If it needs to be done cross server, change the EXEC command to {servername}.{databasename}.{schema}.DiallerDelete etc/
Here we can test it.
SQL
-- Insert Data
INSERT INTO Customer(CustomerName,CustomerStatus) SELECT ' Name 1',0
INSERT INTO Customer(CustomerName,CustomerStatus) SELECT ' Name 2',0
INSERT INTO Customer(CustomerName,CustomerStatus) SELECT ' Name 3',0
UPDATE Customer SET CustomerStatus=2 WHERE CustomerID=1
UPDATE Customer SET CustomerName=' Name 4' WHERE CustomerID=2
DELETE FROM Customer WHERE CustomerID=3
--Review Data
SELECT * FROM Dialler
SELECT * FROM Customer
SELECT * FROM CustomerAuditResults
| Dialler Records | |||
| CustomerID | CustomerStatus | CustomerName | DiallerStatus |
| 1 | 2 | Name 1 | 0 |
| 2 | 0 | Name 4 | 0 |
| Customer Records | ||
| CustomerID | CustomerName | CustomerStatus |
| 1 | Name 1 | 2 |
| 2 | Name 4 | 0 |
| Audit Records | ||||
| CustomerAuditID | CustomerAuditType | CustomerID | CustomerName | CustomerStatus |
| 1 | Record Created | 1 | Name 1 | 0 |
| 2 | Record Created | 2 | Name 2 | 0 |
| 3 | Record Created | 3 | Name 3 | 0 |
| 4 | Record Updated | 1 | Name 1 | 2 |
| 5 | Record Updated | 2 | Name 4 | 0 |
| 6 | Record Deleted | 3 | Name 3 | 0 |
