Microsoft Office Tutorials and References
In Depth Information
Caution If you accidentally delete all the rows from your table, you might be in trouble.
Once the rows are deleted, they can’t be undeleted. There isn’t really an Undo function for
a database like you find in Excel. Pressing Ctrl+Z will not undo your changes. There are
techniques (for example, using transactions) that an advanced database programmer can
use to allow you to recover from this type of error, but in general once the rows are deleted,
it’s best to assume they’re gone.
This example deletes all the rows that have a DateUpdated value that is earlier than 31
Delete From Customers
Where DateUpdated <= ’31-Dec-2002’
In this chapter, you learned a little bit about how relational databases such as Microsoft Access
and Microsoft SQL Server work. You also learned about the Structured Query Language
more commonly referred to as SQL . This language defines statements that allow you to
retrieve data from a database ( Select ), add data to a database ( Insert ), change data in the
database ( Update ), and remove data from the database ( Delete ).