I have two different tables in two separate databases with around 1.5 million records each. (BTW: im working on oracle databases)
The objective is to check if every record present in table A is also present in table B. Since the tables exist in different databases, I think I cannot calculate the "difference" between the two of them, so what im currently doing is selecting the column I need from each database and storing all the rows on separate text files. Then, I load the content of one of the files on a dictionary (using python) and then iterate the other file checking if every line is present on the dictionary.
I would like to make this more simple, perhaps directly on a stored procedure in the database. My main concerns are:
- I don't know if PL/SQL associative arrays are as efficient as the dictionary (im assuming python dictionaries have constant lookup time)
- The fact that tables exist on different databases makes me think that it would be impossible to "reach" the contents of table B if the stored procedure is on the database of table A, or viceversa.
Thanks in advance for any suggestion!