Refining the Process - Set up before Touching SQL

1. Make your own copy of the Original Database - yes, you own copy.
Best backup the file.
Then detach or disconnect SQL Services.
Take a copy of both .log file and the database.

Make a copy for your own use and make a copy for the vault.
Leave the original on the server.

Never touch the - Just back it up and work with copies of the this.

2. Take some steps. I do this. I will select and make tables for each parish eg, 40 i take all the records from the big data table and make my tbl40 dumping all the records from the big table into this.

SQL is called  SELECT INTO tbl40 FROM Bigtable where ParishID=40

This sql statement will automatically create a new table (tbl40) with all fields and structure of the "bigtable"

So we do this for all the parishes.
This allows us to work with subsets of the data, allowing control and - just in case you make a bad "UPDATE" or "DELETE"  then you just have to worry about only these subsets.

Lets us say you did this:

Update Bigtable Set ParishID='090', Name='john'

Then you would be in a really big mess, because there is no WHERE Clause and this means you have update all the record with the same values.

However if this was a subset, you can always say - oh well! this was just one set, let me start with a fresh copy - from the backup.