Using a while loop with SQL cursors? - sql

Question

I am creating an sql script , I have 2 cursors to loop through data a table cursor and a company cursor .
I am having issues putting the company cursor together using while loops to copy data into the schema
I need to answer the below questions using an If Statement
Does the table have a companyID column? an if statement checking for company id
if yes then copy data based on companyID in cursor
I have a #firstLoop declared
Here is my cursor specific code
DECLARE #firstLoop BIT
SET #firstLoop = true
----------- Cursor specific code starts here ------------
-- company cursor
declare copyCompanyDataCursor CURSOR fast_forward FOR
SELECT ID from #CompanyIDs;
open copyCompanyDataCursor
fetch next from copyCompanyDataCursor into #Company_Id;
WHILE ##FETCH_STATUS = 0
BEGIN
declare #processorder int;
declare #tablename varchar(500);
-- table cursor
declare copyTableDataCursor CURSOR fast_forward FOR
SELECT processorder,tablename from #TableList4 order by processorder;
open copyTableDataCursor
fetch next from copyTableDataCursor into #processorder, #tablename;
while ##FETCH_STATUS = 0
BEGIN
SET IDENTITY_INSERT [c365online_script1.dbo.tCompany] OFF
-- Does the table have a companyID column? if statement checking for company id
-- if yes then copy data based on companyID in cursor
-- if no check if this is the first time through company loop and copy all data
-- if #firstloop company exists look at information schema
-- insert into c365online_script1.dbo.tCompany(selec
EXEC('INSERT ' + #Destination_Database_Name + '.dbo.' + #tablename + ' SELECT * FROM ' + #Source_Database_Name + '.dbo.' + #tablename + ')')
-- company logic
SET IDENTITY_INSERT [c365online_script1.dbo.tCompany] ON
FETCH NEXT FROM copyTableDataCursor into #processorder,#tablename;
END
close copyTableDataCursor;
Deallocate copyTableDataCursor;
--INSERT INTO c365online_script1.dbo.tCompany
--SELECT *
--FROM production2.tCompany
--WHERE ISNULL(CompanyID, 0) = 0 -- copy all data where id is equal to zero
--#Destination_Database_Name
--
--EXEC(INSERT + #Destination_Database_Name + '.dbo.' + #tablename + ' SELECT * FROM ' + #Source_Database_Name + '.dbo.' + #tablename + ' WHERE ' + #Source_Database_Name + '.dbo.' + #tablename + '.CompanyID = ' + #Company_Id + ')'
SET #firstLoop = false;
FETCH NEXT FROM copyCompanyDataCursor into #Company_Id;
END
CLOSE copyCompanyDataCursor;
DEALLOCATE copyCompanyDataCursor;

Answer 1

I suggest you replace both the CURSORS with while loop.
CURSORS in SQL Server cost performance very badly instead replacing them with temporary table with While loop will certainly boost the performance and an easier type of coding you will have to write.
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