every single row) will be unique - no other record will have the same value. Note that when you split up a table into two or more smaller tables, the first thing you have to do is to check that each of the tables you have got has a primary key, a field whose value for every single record (i.e. It really helps you to ‘visualise’ the problem. It is a very good idea to put some real or made-up records into the tables you have identified as part of your E-R analysis. In the diagram below, we have a ‘one-to-many relationship’. ‘Entity’ is just a name for a table, so this diagram shows the relationship between entities, or tables. We can draw a diagram of this (called an E-R diagram, or Entity-Relationship diagram). One way to split the table is to have a table for members and a table for dogs. We can have one big record in one table, or split the big record into two parts and link them together (using a special link called a 'foreign key'). However, there is something that can be done about it! Having two smaller tables is no different to having one big table, as long as we link them (or ‘relate’ them - hence the term ‘relational database’). There are problems with flat file databases. Back Relational databases versus flat file databases
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