Warehouse Load Commandments

Thou shalt not put stand-alone codes in the database.

Always import code values along with their English explanations if possible.

Thou shalt not put data into generically named columns like Value1 and Value2.

Every single column should have a clear and understandable name such that the meaning of the values in that column are entirely unambiguous even without having to consult the data dictionary.

Thou shalt not use 1 or 0 to represent Boolean values.

Use only “Yes” and “No”.

Thou shalt not place textual filter data into fact tables.

Thou shalt not place dates into fact tables without an appropriate connection to a date dimension.

The exception here is datetime stamps. When you need high temporal precision, datetime can exist as a degenerate dimension.

Thou shalt not allow flags and acronyms into the database if possible.

Systems are usually filled with all kinds of flags and other acronyms that require expertise to decipher. Usually a front end will decode these flags for a user. These values do not belong in the data warehouse and need to be translated as part of the cleansing process.