Monday, 4 November 2013

Saving a record in the Database using XML


In this articel i will explain how we will save a record in the data base when the record is sent in xml format from front end using stored procedure
First take a new stored procedure. When we take a new stored procedure we will get the following default document



SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:                    <Author,,Name>
-- Create date: <Create Date,,>
-- Description: <Description,,>
-- =============================================
CREATE PROCEDURE <Procedure_Name, sysname, ProcedureName>
            -- Add the parameters for the stored procedure here
            <@Param1,sysname,@p1> <Datatype_For_Param1,int> = <Default_Value_For_Param1, , 0>,
            <@Param2,sysname,@p2><Datatype_For_Param2, int> = <Default_Value_For_Param2, , 0>
AS
BEGIN
            -- SET NOCOUNT ON added to prevent extra result sets from
            -- interfering with SELECT statements.
            SET NOCOUNT ON;

    -- Insert statements for procedure here
            SELECT <@Param1, sysname, @p1>, <@Param2, sysname, @p2>
END
GO

Now we will make changes to the given default document as per our requirements.
Let’s name the stored procedure. We have to write the stored procedure name after the command
CREATE PROCEDURE
We can give our own desired name. Then the stored procedure would be created with that name.
CREATE PROCEDURE StoredProcedureName
As the data is received in the form of xml we need to declare an xml variable and a flag to note its status.
@xmlParam xml,
@flag int
In order to use exceptional handling we will begin a try block. The begin try block is written as
BEGIN TRY
Now we will declare another int variable.
DECLARE @hdoc AS INT
We will execute the preapred xml document in the following way
EXEC sp_xml_preparedocument @hdoc OUTPUT,@xmlparam
Now declare a temporary table with the required number of columns and their data type.
DECLARE TempTable Table(ColumnName Datatype)
I have created a temporary table with column name as RoleName and its datatype as nvarchar(150)
DECLARE @TemporaryTable TABLE(RoleName NVARCHAR(150))
Insert the xml column into the temporary table.
Here we need to give the dataset name that we have given in the generated xml using C#.NET
Then the whole command is
INSERT INTO @TemporaryTable
SELECT * FROM OPENXML (@hdoc,'/DatasetName/Table1',2) WITH (RoleName NVARCHAR(150))
Once the data is stored in the temporary table we will remove the xml document.
EXEC sp_xml_removedocument @hdoc
If the flag equals 1 i.e., the data is inserted into the temporary table successfully, we will move to insert the data in the original table.
IF @flag=1
Here we will begin the insertion of the record into the original table.
BEGIN
Now we will insert the record into the original table, where it is selected from the temporary table.
INSERT INTO tblRoleNames(EmployeeRoleName)
SELECT RoleName FROM @TemporaryTable
If the record is successfully inserted into the table we have to send a success message to the front end which will be displayed in a dialog box. For this we will select 1
SELECT 1
If there are any errors in the saving the record the catch block will be called automatically and it returns a value -99 which shows that the syatem has failed to store the given name.
BEGIN CATCH
                        SELECT -99
END    CATCH
And finally we will close the begin that we have intiated at the beginning of the stored procedure
END

Now will have a look at the entire stored procedure

USE [DatabaseName]
GO
/****** Object:  StoredProcedure [dbo].[ StoredProcedureName]    Script Date: 11/05/2013 12:11:40 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:                    <Author,,Name>
-- Create date: <Create Date,,>
-- Description: <Description,,>
--EXEC StoreProcdedureName
=============================================
CREATE PROCEDURE [dbo].[StoredProcedureName]
            -- Add the parameters for the stored procedure here
            @xmlParam xml,
            @flag int
           
AS
BEGIN
            -- SET NOCOUNT ON added to prevent extra result sets from
            -- interfering with SELECT statements.
            SET NOCOUNT ON;
            BEGIN TRY
                        DECLARE @hdoc AS INT
                        EXEC sp_xml_preparedocument @hdoc OUTPUT,@xmlparam
                        DECLARE @InsertRoleName TABLE(EmployeeRoleName NVARCHAR(150))
                       
                        INSERT INTO @InsertRoleName
                        SELECT * FROM OPENXML (@hdoc,'/DatasetName/Table1',2) WITH (EmployeeRoleName NVARCHAR(150))
                        EXEC sp_xml_removedocument @hdoc
                        IF @flag=1
                        BEGIN
                                                INSERT INTO tblRoleNames(EmployeeRoleName)
                                                SELECT EmployeeRoleName FROM @InsertRoleName
                                                SELECT 1

                        END
            END TRY
            BEGIN CATCH
                        SELECT -99
END    CATCH
END
After executing once the stored procedure with the given name is saved in the database. Then change the command create to alter
ALTER PROCEDURE StoredProcedureName

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