I have a table with the following columns: ID, text1, text2. 
What to do in order to make (text1,text2) unique, for example: values (1,a,b), (2,b,b), (3,a,a) are allowed, but (4,a,b) will not be inserted because (a,b) is repeating?
I have a table with the following columns: ID, text1, text2. 
What to do in order to make (text1,text2) unique, for example: values (1,a,b), (2,b,b), (3,a,a) are allowed, but (4,a,b) will not be inserted because (a,b) is repeating?
 
    
    You can have a unique composite key:
ALTER TABLE my_table
ADD CONSTRAINT uc_my_table UNIQUE (id, text1, text2)
