SQL Guide : Database concepts : Summary
  
Summary
This brief introduction to relational databases has explained the concepts that you need to start using a relational database. You should now be able to answer the following questions:
What are tables, rows, and columns?
Can you work with data in more than one table at a time?
How do transactions help keep data consistent?
Why do we write (“log”) transaction data to the disk drive?
See also
Database concepts