This means that instead of hitting your database for the Brother Cell Phone List same record 100 times, the caching layer will hit your database once and then serve up the cached record the other 99 times. Memcached is used for this most of the time and has great Brother Cell Phone List performance, but you need to take extra steps to make sure that it clears it's cache correctly. Just as files can be organized in different ways, so databases can also be Brother Cell Phone List organized in ways to best fit their use. The four most common arrangements Brother Cell Phone List are, hierarchical, network, relational and object oriented.
Hierarchical Database In a hierarchical database, fields or Brother Cell Phone List records are arranged in related groups resembling a family tree, which Brother Cell Phone List child records subordinate to parent records. The parent record at the top of the database is called the root record. Used principally on mainframes, hierarchical databases are the oldest of the four types. They are still used in some types passenger reservation systems. In Brother Cell Phone List hierarchical databases, accessing or updating data is very fast, because the relationship have been predefined. However because the structure must be defined in advance, it is quite rigid.
There may be only one parent per child, and no relationships Brother Cell Phone List among the child records are possible. Moreover, adding new fields to databases, records requires that the entire database be redefined. Network database A network database is similar to hierarchical database but each child record can have more than one parent record. This Brother Cell Phone List a child record which in network database terminology is called a member, may Brother Cell Phone List be reached through more than one parent which is called an owner.