Computers

Normalization Normalization is a method for organizing info elements in a database into panels. Normalization Avoids Duplication of Data The same data is careened in multiple lines of the database Insert anomalousness A point active an entity bunsnot be inserted into the table without first inserting cultivation about(predicate) other entity Cannot enter a guest without a complete(a) sales effect take away Anomaly A record cannot be deleted without deleting a record about a related entity. Cannot delete a sales order without deleting each of the clients in manakination. Update Anomaly Cannot update information without changing information in many places. To update customer information, it must be updated for each sales order the customer has placed Normalization is a three stagecoach performance After the first stage, the data is said to be in first normal form, after the plunk for, it is in indorsement nor mal form, after the third, it is in third normal form in the lead Normalization 1. Begin with a list of all of the fields that must appear in the database. withdraw of this as whizz life-size table. 2. Do not complicate computed fields 3. One place to dismount getting this information is from a printed schedule used by the system. 4. Additional attributes also those for the entities described on the document can be added to the database.

in advance Normalization Example See Sales severalise from below: [pic] Fields in the original data table bequeath be as follows: SalesOrd erNo, Date, CustomerNo, CustomerName, Custom! erAdd, ClerkNo, ClerkName, ItemNo, Description, Qty, UnitPrice Think of this as the baseline one large table Normalization: First Normal wee-wee reprint Repeating Groups into New Tables. Repeating Groups Fields that may be repeated several times for one document/entity reach a new table containing the repeating data The primary signalize of the new table (repeating group) is always a composite primal; Usually document...If you want to get a full essay, order it on our website: OrderCustomPaper.com

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