Sql database design for null column on first insertion

Question

We have a table in an sql database with three columns: t1c1 , t1c2 , and t1c3 .

When I insert new rows in the table I will fill the values for first two columns ( t1c1 and t1c2 ), but the third column ( t1c3 ) will always be null upon first insertion. After that something happens inside the system and it will fill the value for t1c3 .

My question is about normalization. Should the t1c3 column really be part of table1 or should it be part of another table ( table2 ) with just one column ( t2c1 ) which is equal to ( t1c3 ).

Answer 1

You'd need two columns: one with the key from table1 , and one with the tcl3 value, so you could relate the values in table2 back to the correct rows in table1 . However, it doesn't seem necessary to do that in this case.