orf is a primary key. It is a unique string that links the tables.
Essentially, the setup is this: I am presented with data called
transcription profiles. These contain two columns: orf, which is a unique
representation of a biological gene, and induction, which is a number.
Now, unfortunately,
If orf is not associated with a primary key or unique
index, the possible combinations might well exceed
14,000. For example, if 3 records in yeast1 and 4
records in temp share the same orf value, the query
will update yeast1 12 times (i.e. the 3 yeast1 records
will be updated 4 times each).
Can
