SQL job to ALTER VIEW - tsql

Question

On a weekly base, data is updated from a source into one of the two identical tables: Table_ODD or Table_EVEN. A view transfers data from the active table to a reporting tool. Which table is currently active is stored in a table.
So the view is either like this:
Create View [dbo].[V_ReportData] AS SELECT * FROM [Table_ODD] -- for odd-week
or
Create View [dbo].[V_ReportData] AS SELECT * FROM [Table_EVEN] -- for even-week
The switch may only be performed after approval of the updated data, and will be done by an administrator
who will manually start the job.
I had like to create a job that will do the switch. I have tried this code:`
Declare #NumberOfTables as int
,#ActiveTable as nvarchar(100);
Set #NumberOfTables = (Select Count(*) from [Table_Status] where Upper([Status]) = 'ACTIVE' ) ;
if #NumberOfTables = 1
BEGIN
Set #ActiveTable = (Select UPPER([TABLE_NAME]) from [Table_Status] where Upper([Status]) = 'ACTIVE' );
END;
if #ActiveTable = 'TABLE_EVEN'
BEGIN
ALTER View [dbo].[V_TABLE_] AS
SELECT *
FROM [dbo].[TABLE_ODD]
UPDATE [Table_Status]
Set [STATUS] = 'ACTIVE'
Where [TABLE_NAME] = 'TABLE_ODD'
UPDATE [Table_Status]
Set [STATUS] = 'PASSIVE'
Where [TABLE_NAME] = 'TABLE_EVEN'
END
if #ActiveTable = 'TABLE_ODD'
BEGIN
ALTER View [dbo].[V_TABLE_] AS
SELECT *
FROM [dbo].[TABLE_EVEN]
UPDATE [Table_Status]
Set [STATUS] = 'ACTIVE'
Where [TABLE_NAME] = 'TABLE_EVEN'
UPDATE [Table_Status]
Set [STATUS] = 'PASSIVE'
Where [TABLE_NAME] = 'TABLE_ODD'
END
`
But The ALTER VIEW statement may not be included in any part of the coding.
So I think the ALTER VIEW statement should be in a separate step.
But that step must be activated conditionaly, namely based on the condition which table is active.
In short something like this:
if #ActiveTable = 'TABLE_EVEN'
then step 2
else step 3
DROP and CREATE view is not recommended because of authorizations that are granted to the view. With a DROP VIEW statement, all authorizations are drop as well.
How can I achieve this?

Answer 1

I took me a little while , but found the answer!
I had to create multiple steps first, before I could switch to the specific job step based on an error-code.
List of job steps
step 1: check if switch is valid, e.g. only one table is Active and DateTimeStamp of passive table (which should be the last updated) is more recent then active table
Declare #NumberOfTables as int
,#ActiveTable as nvarchar(100)
,#Update_DateTime_Active as datetime
,#Update_DateTime_Passive as datetime;
Set #NumberOfTables = (Select Count(*) from [Table_Status] where Upper([Status]) = 'ACTIVE' ) ;
if #NumberOfTables = 1
BEGIN
set #Update_DateTime_Active = (Select [UPDATED] from [Table_Status] where Upper([Status]) = 'ACTIVE' );
set #Update_DateTime_Passive = (Select [UPDATED] from [Table_Status] where Upper([Status]) <> 'ACTIVE' );
END
IF #Update_DateTime_Active > #Update_DateTime_Passive
RAISERROR ('Status Active table not compatible with Update DateTimestamp',16,2)
if #NumberOfTables <> 1
RAISERROR ('Tables Data_ODD and Data_EVEN have same status',16,3)
Step 2: determin which table is currently active
Declare #NumberOfTables as int
,#ActiveTable as nvarchar(100);
Set #NumberOfTables = (Select Count(*) from [Table_Status] where Upper([Status]) = 'ACTIVE' ) ;
if #NumberOfTables = 1
BEGIN
Set #ActiveTable = (Select UPPER([TABLE_NAME]) from [Data_Table_Status] where Upper([Status]) = 'ACTIVE' );
END
if #ActiveTable = 'DATA_EVEN'
BEGIN
RAISERROR('Now switch VIEW to table ...ODD',1,1)
END
This step determin the next step to be taken in the advanced settings of the step:
On succes action: goto step 3
on Error action: goto step 5
Remember: when ..EVEN is active, an error is raised, causing the job to go to step 5 (which is activating ..ODD)
Step 3: alter view to EVEN
ALTER View [dbo].[V_Data_] AS SELECT * FROM [dbo].[Data_EVEN]
step 4: updated status table (change status of ODD to Active, and EVEN to Passive)
UPDATE [Data_Table_Status]
Set [STATUS] = 'ACTIVE'
Where [TABLE_NAME] = 'Data_EVEN'
UPDATE [Data_Table_Status]
Set [STATUS] = 'PASSIVE'
Where [TABLE_NAME] = 'Data_ODD'
Step 5: alter view to ODD
step 6: updated status table (change status of ODD to Active, and EVEN to Passive)