Datatypes are a subject that

confuses many people. There are many types and many sub-types. A type

is a basic datatype like NUMBER. A sub-type is derived from a type. An

INTEGER is a sub-type of NUMBER. A sub-type usually add a constraint to

a type and that creates the new sub-type; for INTEGER, only whole

numbers are allowed.

In 10g, the five numeric types that you

will most commonly use are: NUMBER, PLS_INTEGER, BINARY_INTEGER,

BINARY_FLOAT and BINARY_DOUBLE. You would declare and use any of these

in the same manner, although the BINARY_FLOAT and BINARY_DOUBLE add a

few extra features that I cover below.

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