Please Explain Script

Question

Hello,

Can you please explain to me what the script below does? If possible, line by line.

Thank you in advance.

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set nocount on

go

select distinct 'Print ''Start: ' + a.name + '''' + 
char(13) +  'Insert into Databasename.PROD_OCS.' + 
a.name + char(13) +  ' Select * From Databasename.PROD_OCS.' + a.name  + char(13)
        from sys.sysobjects a, sys.sysindexes b   
where a.xtype = 'U'     
and a.id = b.id 
and b.rowcnt > 0

Answer 1

I'm working under the presumption that "Databasename" for the insert into Databasename.PROD_OCS is supposed to be different than "Databasename" for the select * from Databasename.PROD_OCS

For each user table (that's the "sys.sysobject a" bit) in the current database that has any rows ("sys.sysobjects b" and "and b.rowcnt > 0"), it is generating an insert into select statement that, were you to execute it, would load the table in the PROD_OCS schema of one database from the identically named table in the PROD_OCS schema, having the same number and type of columns, in another database.

It's using DISTINCT because the join between a and b can result in multiple rows for each table (a table can have 1 or more rows in sys.indexes), but the script only wants one "insert into select" statement per table.

Because this snippet is just generating the statements and not executing them, it's safe to run as you have presented it. Then you can take a look at the output to see what it would do.

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