Compressed database means the maximum effort to reduce data redundancy. For example if I consider a student database then I must have to ensure that in the whole database each word only exist for onetime.
We will use the index of word in the database table. Using the index we can find out the word in the data dictionary. Data Dictionary contain several word category. Data dictionary is maintained to handle the word used on other table. Almost in every database contain Noun type data or numerical or alphanumerical data. So if we map the Noun type data based on category and put them only one time in a database i.e. we want to use the word id instead of name such as Md Nazmul kibria. If we place in the name column of a table the id 012 of Md Nazmul Kibria we can save storage. Another thin is that in a database there may same name or same name segment for several user. For example in a student database contain 1000 data; in this thousand data the name Islam repeats in 50 data. So if I insert Islam in 50 different row of a table it is reduntant approach. Instead saving 50 data if I use the index id of Islam (015) it is more space saving approach. If I have 3 or 4 different languages used to represent this student database in 3 or 4 different languages; in this case data dictionary and using word index is much efficient approach in saving time and space in the database.
I will post later on this topic in detail with some examples.
1 comment:
hmm good ...but need2 make it more clear.....
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