Normalization
Normalization is a series of steps
followed to obtain a database design that allows for efficient access and
storage of data. These steps reduce data redundancy and the chances of data
becoming inconsistent.
Denormalization
Denormalization is the process of introducing redundancy into a table by incorporating data from a related table.
Tables are usually denormalized to prevent expensive SQL join operations between them.
One
should always normalize to third-normal form and only apply denormalization
selectively as a last resort if performance problems are experienced. Remember
that denormalizations is not free and introduces the following problem into the
design:
§
More disk space is used
as the same data is duplicated in more than one table
§
You run the risk that
the data can get "out of sync"
No comments:
Post a Comment