Once you have a collection of fields now you need to break these fields into the tables to which they belong. If you remember one of the the rules for brainstorming the field was to write down what the people called these fields. Here is where this pays off.
Use the names people gave their fields
People are interesting they categorize everything and then use these groupings in their names for fields. I have yet had a group start with just the word name, unless we were making one table. They don’t call the name field just name they say things like customer name, product name, company name. While they are brainstorming fields they will unconsciously organize the fields for you.
Then all you have to do is gather the fields by their common name. It will make you look like a genius, but this is just unlocking the client’s potential. The names of the tables are simply the common name given to all of the fields, customer name, customer address, etc. Gather them by using a rectangle and putting the name of the fields inside the box.
The primary key
Once the tables are organized it now comes time to designate the primary key of the table. I recommend that all tables have a primary key, even if you have to make one up. The definition of the a primary key is the field or group of fields that uniquely identifies each row in a table. For things like customers it could be a customer id. In each box indicate the primary key field by putting PK next to the primary key field. Generally one field should be it for a primary key, but some tables have complex relationships to manage and may require a multiple field key.
Once you have gone down and put all of the fields into the table rectangles and indicated the primary key fields, the next steps is to draw the relationships between the tables. We will go into that next time.
Related posts:
