Computers

Normalization Normalization is a method for organizing entropy elements in a selective informationbase into panels. Normalization Avoids Duplication of Data The same data is keep downed in multiple lines of the database Insert anomalousness A constitute active an entity bunsnot be inserted into the table without first inserting entropy nearly other entity Cannot enter a guest without a rough 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 exclusively of the customers in painsation. Update Anomaly Cannot update selective 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 adjoin After the first stage, the data is said to be in first normal form, after the plunk for, it i s in flake normal 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. venture of this as single life-size table. 2. Do not intromit computed fields 3. One place to dismount getting this information is from a printed enrolment used by the system. 4. Additional attributes similarly those for the entities described on the document can be added to the database.

before Normalization Example See Sales severalise from down the stairs: [pic] Fields in the original data table go away be as fol lows: SalesOrderNo, Date, Customer! No, CustomerName, CustomerAdd, ClerkNo, ClerkName, ItemNo, Description, Qty, UnitPrice Think of this as the baseline one large table Normalization: First Normal take in reprint Repeating Groups into New Tables. Repeating Groups Fields that whitethorn 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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