Re: Constraints validated

Even I do not understand this.If you have defined a column not null one cannot insert null values

.But, there is an option where one can use the keyword NOVALIDATE

This means that one can create a table with a column which has no constraints( in our case its not null constraint) insert null values and then add the constarint
with the keyword NOVALIDATE this will make sure that it will not validate any previous null values in the column and will start with the latest one.

This is the only possible way that one can have null values in not null column

Example:
alter table aa1 modify id number constraint NN not null NOVALIDATE

Table aa1 was first cretaed with no constraints and a null value was inserted and tehn constraint was added with the above syntax. Received on Mon Jan 30 2006 - 17:00:48 CST