I wanted to create a tool for some fields like SIFT, Phenotype, etc..so for example I know Phenotype will have "Text" values or SIFT will have some determined values from a drop down list...but what about Chrom Positions? what are some valid sample values for that? so I can know what type I can use for it.
Since it sounds like you are the one designing the database, you can make this a number of ways. The simplest is probably to reduce it to two variables, likely two decimals.
See this hemoglobin example for a chromosomal locus example.
Chromatid can be easily represented as a decimal, where the integer portion is the chromosome number, and the decimal portion corresponds to the chromatid and arm.
The chromosomal locus can be another decimal, such as 15.5 for the example above.
This is of course one way, and there are many other ways you could do this.