How to make sure several SELECTs are isolated?
When we have to use several different SELECT queries to get data from various locations in the database, how to make sure they are isolated from queries such as INSERT, UPDATE or DELETE so that we can be sure that data selected are consistent with each other and not changed in between?
I know I can use transaction to achieve the same effect for INSERT, UPDATE and DELETE so changes are applied as a whole or not. But does it isolate SELECTs as well?
For example, 3 SELECT queries return 3 different values, either:
1, 3, 5
Or:
2, 4, 8
A update query is constantly switching the values. How to make sure I get either:
1, 3, 5
Or:
2, 4, 8
But not anything in between such as: 2, 3, 5, nor 2, 4, 5, etc.
I know I can get those updates in a transaction but I want double check.
So would it work if I put those 3 SELECTs in a transaction?
I know I can use transaction to achieve the same effect for INSERT, UPDATE and DELETE so changes are applied as a whole or not. But does it isolate SELECTs as well?
For example, 3 SELECT queries return 3 different values, either:
1, 3, 5
Or:
2, 4, 8
A update query is constantly switching the values. How to make sure I get either:
1, 3, 5
Or:
2, 4, 8
But not anything in between such as: 2, 3, 5, nor 2, 4, 5, etc.
I know I can get those updates in a transaction but I want double check.
So would it work if I put those 3 SELECTs in a transaction?
1. Global Movies Database = $489.95 = 1.5 GB data + 65.9 GB images.
2. World Hotels Database = $589.95 = 1.54 GB data + 71.4 GB images.
3. Auto Parts Database = $489.95 = 15.8 GB data + 30.4 GB images.