Oracle - Why not null constraint cannot be applied at the table level??
Why not null constraint cannot be applied at the table level??
Ans:
All Constraint gives the logical view to that particular column but NOT NULL get assigned to the structure of the table itself, that's why we see NOT NULL constraint while Describe command is issued against the table and no other constraint will be seen.
So all the constraints can be applied at table level and column level except NOT NULL that can be acheived only at the column level and not at the table level
Ans:
All Constraint gives the logical view to that particular column but NOT NULL get assigned to the structure of the table itself, that's why we see NOT NULL constraint while Describe command is issued against the table and no other constraint will be seen.
So all the constraints can be applied at table level and column level except NOT NULL that can be acheived only at the column level and not at the table level
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