简单的Oracle（sqlplus）约束问题…需要更​​改并添加变量> 0

Question

I'm trying to add this into my Oracle database (in SQL*Plus) but how do i make the constraint? i tried check but it wasn't working. Here's what i got though:

-- Add a new attribute years of experience to table Tech_personnel, and enforce it to be a positive value (ie, > 0).

my solution:

ALTER TABLE Tech_personnel ADD years_of_experience NUMBER(30);

ALTER TABLE Tech_personnel ADD CONSTRAINT non_neg
CHECK(years_of_experience > 0);

Answer 1

What, exactly, is not working?

SQL> create table tech_personnel( col1 number );

Table created.

SQL> ALTER TABLE Tech_personnel ADD years_of_experience NUMBER(30);

Table altered.

SQL> ALTER TABLE Tech_personnel ADD CONSTRAINT non_neg CHECK(years_of_experience > 0);

Table altered.

SQL> insert into tech_personnel values( 1, -1 );
insert into tech_personnel values( 1, -1 )
*
ERROR at line 1:
ORA-02290: check constraint (SCOTT.NON_NEG) violated


SQL> insert into tech_personnel values( 1, null );

1 row created.

SQL> insert into tech_personnel values( 1, 1 );

1 row created.

Perhaps you also want to ensure that the YEARS_OF_EXPERIENCE is not NULL?