He could create foreign keys, which are basically columns in a table with values that identify a record from another table.
However, even without foreign keys you can construct queries that link data from multiple tables together.
The answer is GIGO or the garbage in, garbage out. It is an idea regular to software engineering and science: the nature of yield is dictated by the nature of the information. In this way, for instance, if a scientific condition is disgracefully expressed, the appropriate response is probably not going to be right. It has a tendency to be utilized when discussing information section and databases. Essentially it implies that in the event that you enter off base or wrong information then you have truly entered waste.
