Left typed column. Contains info about column name and extractor
When joining F[L] and F[R], to unsure type safety several types are required.
First of all we need to know the original type L to extract value from F container.
Second, if L is a tuple of (A, b), we can de-compose extractor into 2 extractors - for A and for B respectively
Third, we need to know the column type itself to prevent joining by incompatible types
O
original type of left operand in join
E
decomposed type, is used when unapplying original extractor
Left typed column. Contains info about column name and extractor When joining F[L] and F[R], to unsure type safety several types are required. First of all we need to know the original type L to extract value from F container. Second, if L is a tuple of (A, b), we can de-compose extractor into 2 extractors - for A and for B respectively Third, we need to know the column type itself to prevent joining by incompatible types
original type of left operand in join
decomposed type, is used when unapplying original extractor
column type