Typically, each block performs a logical action in he program. The other sections are optional. We may also find in the executable section certain kinds of statements such as assignments, branches, loops, procedure calls, and triggers, which are all described below.
Every variable has a specific type associated with it.
That type can be either One of the types used by SQL for database columns. The same as the type of some database column. The initial value of any variable, regardless of its type, is NULL . The length is required, and there is no default. In this case, it is essential that the variable have the same type as the relation column.