Insert into tables based on updating list (table) - sql-server

Question

Ive been struggling with this one for a while and appreciate any help.
I have a table that continuously get updated with a list of table names (same table can occure several times) that has been updated with new data recently in Database 1.
I want to create a query that checks this update list and inserts the data from updated tables in Database 1, into corresponding tables in Database 2. And loops through until the end of the list.
The list can look like this:
ID Table TimeStamp
----------------------- -------- -----------------------
0313778E-CB68-E811-910D Customer 2018-07-10 13:27:28.567
0313778E-CB68-E811-910D Customer 2018-07-10 13:28:58.010
194DD17A-CE68-E811-910D Order 2018-07-10 13:27:28.567
0EBB391D-126B-E811-910D Product 2018-07-10 13:28:58.010
4AAE33A5-CE68-E811-910D Customer 2018-07-10 13:27:28.567
DFA2A68C-056B-E811-910D Order 2018-07-10 13:28:58.010
C2CFECB6-CE68-E811-910D Employee 2018-07-10 13:27:28.583
To make it worse, the tables in Database 2 don't have same amount of columns as Database 1.
Ive been working on both MERGE and Cursor, as well as dynamic SQL. Im new to these so keep getting stuck. I think dynamic SQL + CURSOR is the best way to go. All of this will result in a stored procedure. Maybe there is a better way of doing it? Anyway, this is what I have:
Declare #Source_TableName_Column --this one contains the Database 1 tables as well as the correct columns needed to fill matching table in Database 2.
Declare #InsertInto NVARCHAR(MAX),
#TargetTable NVARCHAR(MAX)='Select name from Database2.sys.all_objects', --list of tables I have in Database 2
#Columns NVARCHAR(MAX) = 'Select name from Database2.sys.all_columns', --list of columns I have in Database 2 (same names as it is in SourceTable in Database 1)
;
DECLARE TableInsert CURSOR FOR
SELECT distinct SourceTableName from Database3.dbo.UpdateTableList
OPEN TableInsert
FETCH NEXT FROM TableInsert
INTO #TableName
--LOOP
WHILE ##FETCH_STATUS=0
BEGIN
SET #InsertInto = 'insert into Database2.dbo.'+#TargetTable+' '+(#Columns)+' values'+(....)+'' --not sure how to do this variable where i get all the results from SourceTable matching columns in TargetTable in database 2
FETCH NEXT FROM TableInsert
INTO #TableName
END
--CLOSE CURSOR
CLOSE TableInsert
DEALLOCATE TableInsert

Answer 1

This is complex. I would approach it in a simpler fashion than what you are doing. I’d do it your way if scenario involved destination tables with the same schema, but numerous columns, which does not seem to be the case with you.
Here’s what i’d do.
Open cur1
Fetch next from cur1 into #tablename ....
While ##fetchstatus = 0
Begin
If ##tablename= ‘tbl1’
Begin
Insert into database2.dbo.tbl2 values
Select ... from database1.dbo.table1 where ..
End
If ##tablename = ‘tblx’
And so on
Fetch next from cur1 into ...
End

Answer 2

I made a solution that works for me. Some names I have changed here to better fit my description above. I think they are correct, will look through it later and correct it if wrong =)
I am, however, a bit unsure about the delete statement further down in the code.
I have a TempTable based on the update list. I want to delete the rows in the update list after Ive inserted into tables. I have one with two 'where field IN (corresponding field in TempTable' clauses and another one with a 'delete from ... where exists (tempTable). Temptable has two columns but update list has three in total. Whichever is fastest/best?
DECLARE #InsertInto NVARCHAR(MAX);
DECLARE #SourceID NVARCHAR(MAX);
DECLARE #TableAttribute NVARCHAR(MAX);
DECLARE #SourceViewName NVARCHAR(MAX);
DECLARE #TargetTable NVARCHAR(MAX);
DECLARE #SourceTableName NVARCHAR(MAX);
/*-------Create temp table to be used in cursor-------*/
Declare #SQL_TempTable_Insert NVARCHAR(MAX);
IF OBJECT_ID('tempdb..#Cursor_TempTable') IS NOT NULL DROP TABLE #Cursor_TempTable
CREATE TABLE #Cursor_TempTable (
SourceEntity NVARCHAR(MAX) )
/*-------variable to be used in insert step below-------*/
SET #SQL_TempTable_Insert = 'SELECT SourceLogicalName FROM DataBaseC.dbo.REF_ENTITIES_SYNC group by SourceLogicalName'
/*-------Insert into temp table-------*/
INSERT INTO #Cursor_TempTable EXECUTE (#SQL_TempTable_Insert)
/*-------Create temp table from NeworUpdate table-------*/
Declare #SQL_TempTable_NewOrUpdated NVARCHAR(MAX);
IF OBJECT_ID('tempdb.. #TempTable_NewOrUpdated') IS NOT NULL DROP TABLE #TempTable_NewOrUpdated
CREATE TABLE #TempTable_NewOrUpdated (
[ID] NVARCHAR(MAX),
[TimeStamp] DATETIME )
/*-------variable to be used in insert step below in NewOrUpdate temp table-------*/
SET #SQL_TempTable_NewOrUpdated = 'SELECT ID, TimeStamp FROM DataBaseC.dbo.[REF_POSTS_NewOrUpdated] group by ID, TimeStamp'
/*-------Insert into NewOrUpdate temp table-------*/
INSERT INTO #TempTable_NewOrUpdated EXECUTE (#SQL_TempTable_NewOrUpdated)
/*-------Cursor segment-------*/
DECLARE EntitiesInsert CURSOR FOR
SELECT SourceEntity FROM #Cursor_TempTable
OPEN EntitiesInsert
FETCH NEXT FROM EntitiesInsert
INTO #TargetTable
--LOOP
WHILE ##FETCH_STATUS=0
BEGIN
BEGIN TRY
BEGIN TRAN
SET #SourceViewName = (select SourceName from DataBaseC.dbo.REF_ENTITIES_SYNC where Targetname = #TargetTable);
SET #SourceTableName = (select SourceTableName from DataBaseC.dbo.REF_ENTITIES_SYNC where Targetname = #TargetTable);
SET #TableAttribute = stuff(( select ', ' +char(10)+ ac.[name] from DataBaseB.sys.all_columns ac
inner join DataBaseB.sys.all_objects ao on ao.object_id=ac.object_id
where ao.name = #TargetTable and ac.name not in ('ValidFrom','ValidTo')
FOR XML PATH('')
), 1, 1, '')
--Finds DatabaseA table's Primary Key
SET #SourceID = (select c.name
from sys.index_columns ic
inner join sys.columns c on ic.object_id = c.object_id and ic.column_id = c.column_id
inner join sys.indexes i on ic.object_id = i.object_id and ic.index_id = i.index_id
inner join sys.tables t on i.object_id = t.object_id
inner join sys.schemas s on t.schema_id = s.schema_id
where i.is_primary_key= 1 and t.name = #SourceTableName);
SET #InsertInto = 'INSERT INTO DataBaseB.dbo.'+#TargetTable+' ('+#TableAttribute+')
SELECT '+#TableAttribute+' FROM DataBaseA.dbo.'+#SourceViewName+'
where '+#SourceID+' in (select nu.ID from DataBaseC.Inno.REF_ENTITIES_SYNC sync inner join #TempTable_NewOrUpdated nu on nu.SourceEntity = sync.TargetName where sync.TargetName = '''+#TargetTable+''' group by nu.ID )'
EXEC sp_sqlexec #insertInto
--Delete the records from [DataBaseC].[dbo].[REF_POSTS_NewOrUpdated] that we have inserted.
--DELETE FROM [DataBaseC].[dbo].[REF_POSTS_NewOrUpdated]
-- WHERE ID = (select [ID] from #TempTable_NewOrUpdated)
-- AND TimeStamp = (select [Timestamp] from #TempTable_NewOrUpdated)
----alt2
--DELETE FROM [DataBaseC].[dbo].[REF_POSTS_NewOrUpdated]
-- where exists (select * from #TempTable_NewOrUpdated)
--End TRAN
COMMIT
--End TRY
END TRY
--Catch possible errors
BEGIN CATCH
--IF there is an open transaction then roll back and print error messages.
IF ##TRANCOUNT > 0
ROLLBACK TRANSACTION
DECLARE #ErrorNumber INT = ERROR_NUMBER();
DECLARE #ErrorLine INT = ERROR_LINE();
DECLARE #ErrorMessage NVARCHAR(4000) = ERROR_MESSAGE();
DECLARE #ErrorSeverity INT = ERROR_SEVERITY();
DECLARE #ErrorState INT = ERROR_STATE();
PRINT 'Actual error number: ' + CAST(#ErrorNumber AS VARCHAR(10));
PRINT 'Actual line number: ' + CAST(#ErrorLine AS VARCHAR(10));
PRINT 'Actual error message: ' + CAST(#ErrorMessage AS VARCHAR(MAX));
PRINT 'Actual error Severity: ' + CAST(#ErrorSeverity AS VARCHAR(MAX));
PRINT 'Actual error State: ' + CAST(#ErrorState AS VARCHAR(MAX));
END CATCH
FETCH NEXT FROM EntitiesInsert
INTO #TargetTable
END
CLOSE EntitiesInsert
DEALLOCATE EntitiesInsert
GO