Question

I have a three tables

Results: TestID TestCode Value

Tests: TestID TestType SysCodeID

SystemCodes SysCodeID ParentSysCodeID Description

The question I have is for when the user is entering data into the results table.

The formatting code when the row gets the focus changes the value field to a dropdown combobox if the testCode is of type SystemList. The drop down has a list of all the system codes that have a parentsyscodeID of the test.SysCodeID. When the user chooses a value in the list it translates into a number which goes into the value field.

The datatype of the Results.Value field is integer. I made it an integer instead of a string because when reporting it is easier to do calculations and sorting if it is a number. There are issues if you are putting integer/decimal value into a string field. As well, when the system was being designed they only wanted numbers in there.

The users now want to put strings into the value field as well as numbers/values from a list and I’m wondering what the best way of doing that would be.

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Would it be bad practice to convert the field over to a string and then store both strings and integers in the same field? There are different issues related to this one but i’m not sure if any are a really big deal.

Should I add another column into the table of string datatype and if the test is a string type then put the data the user enters into the different field.

Another option would be to create a 1-1 relationship to another table and if the user types in a string into the value field it adds it into the new table with a key of a number.

Anyone have any interesting ideas?

Answer 1

What about treating Results.Value as if it were a numeric ValueCode that becomes an foreign key referencing another table that contains a ValueCode and a string that matches it.

CREATE TABLE ValueCodes (     Value     INTEGER NOT NULL PRIMARY KEY,     Meaning   VARCHAR(32) NOT NULL UNIQUE );  CREATE TABLE Results (    TestID     ...,    TestCode   ...,    Value      INTEGER NOT NULL FOREIGN KEY REFERENCES ValueCodes ); 

You continue storing integers as now, but they are references to a limited set of values in the ValueCodes table. Most of the existing values appear as an integer such as 100 with a string representing the same value ‘100’. New codes can be added as needed.