particular kind of data figure shows the index line field as holding person' name more sophisticated database programs use records with more fields than cardfile has figure shows such recordwhere each line represents distinct field in java programrecords are usually represented by objects of an appropriate class (in crecords would probably be represented by structures individual variables within an object represent data fields fields within class object are called fields in java (but members in and ++key to search for record within database you need to designate one of the record' fields as key you'll search for the record with specific key for examplein the cardfile program you might search in the index-line field for the key "brown when you find the record with this keyyou'll be able to access all its fieldsnot just the key we might say that the key unlocks the entire record in cardfile you can also search for individual words or phrases in the rest of the data on the cardbut this is actually all one field the program searches through the text in the entire field even if all you're looking for is the phone number this kind of text search isn' very efficientbut it' flexible because the user doesn' need to decide how to divide the card into fields figure record with multiple fields in more full-featured database programyou can usually designate any field as the key in figure for exampleyou could search by zip code and the program would find all employees who live in that zip code search key the key value you're looking for in search is called the search key the search key is compared with the key field of each record in turn if there' matchthe record can be returned or displayed if there' no matchthe user can be informed of this fact object-oriented programming this section is for those of you who haven' been exposed to object-oriented programming howevercaveat emptor we cannotin few pagesdo justice to all the innovative new ideas associated with oop our goal is merely to make it possible for you