Two linked tables or one

Question

I need to choose one of the following solutions:
1- T_DOCS(ID_DOC PK, ...) and T_DEST(ID_DOC, DEST) and there are n rows in T_DEST for each element in T_DOCS . For instance: 10k elements per year in T_DOCS with 200 elements in T_DEST, for each element in T_DOCS (20 000 000 per year in T_DEST). The main operation are insert and select.
2- One table T_DOCS with a BLOB field where I put DEST.
What is the best solution?

Answer 1

Solution choice 1 is relational
Solution choice 2 is not
Therfore the only choice is 1
I do not see how choice 2 would be functional unless you know all the DEST elements at one time, insert them all togeter, and do not need to retireve individual elements of DEST in conjunction with the associated element in DOCS. To do this would require parsing of the BLOB which would be a relatively expensive operation.
As is said, "the devil is in the details," so it may be based on how the data is actually used that the parse time is acceptable, that fetching specific individual elements of DEST for elements in DOCS is rare and never part of a join condition so while it may well be that solution 2 will work in some cases based on the information given. However, I do not like it.
If you are going to use a relational database to store data then the data should be stored in a relational manner.
IMHO -- Mark D Powell --