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Tag: constraints

Can’t enable a foreign key in ORACLE SQL

So I have a disabled foreign key (Manager_ID in the table Employees) and I wanted to enable it, but I get this error: ORA-02298: cannot validate (my_username.EMP_MANAGER_FK) – parent keys not found And this is the code: Here’s how the table was created: Answer There are values in the column that are invalid from the foreign key’s perspective. Assuming that

non UNIQUE constraints

So, I got in this situation: I create a table (let say model_a), in this table I have 2 cols (let say col1 and col2). I need a constraint that satisfy this reality: It’s not UNIQUE constraint, you can duplicate the first row. The only one time this constraint active is col1 is the same but col2 is different. Need

Add check constraint related to other column

My table structure is as below I want to add a constraint to this table where only if IsActive=1, GoSequence value can be change. If IsActive=0, GoSequence stays 0. Any help is appreciated. Thanks! Answer Probably the simplest way of expressing that is that either GoSequence must be 0 or IsActive must be 1. So your constraint could look like

How to allow only numbers in (Oracle SQL)

I want to add a integrity constraint which only lets numeric data be added to the Unit_Price. Also, I have a email column in another table, how can I make it so a @ sign is required. Furthermore, if they dont enter email then it should be ‘ ‘unknow@gmail.con’ as default? Edit: Sorry the datatype was supposed to be varchar2

postgresql ERROR: syntax error at or near “PRIMARY”

I’m new to PostgreSQL. I’ve been trying to create tables in a database but some queries give weird errors. the first snippet throws a syntax error but when I add “serial” on the problematic column the error is resolved. Should all primary keys auto-increment in PostgreSQL? This works added serial constraint on songplay_id Answer Should all primary keys auto-increment in

Oracle: When are constraints checked?

In my understanding constraints should generally be checked at the end of a transaction. So, in a simple example where we have one table A with the only column P, which is its primary key, and a table B with the primary key P and the foreign key F on A.P, the following should work (on empty tables): However, Oracle