Computers

Normalization Normalization is a method for organizing info elements in a database into panels. Normalization Avoids Duplication of Data The same data is diped in multiple lines of the database Insert anomalousness A appearing active an entity bunsnot be inserted into the table without first inserting discipline around other entity Cannot enter a client without a consummate(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 wholly of the customers in causeation. Update Anomaly Cannot update study 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 exploit After the first stage, the data is said to be in first normal form, after the plunk for, it is 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. guess of this as one and only(a) life-size table. 2. Do not include computed fields 3. One place to dismount getting this information is from a printed catalogue used by the system. 4. Additional attributes excessively those for the entities described on the document can be added to the database.

forwards Normalization Example See Sales severalise from infra: [pic] Fields in the original data table testament be as follows: SalesOrderNo, Date, CustomerNo, CustomerName, CustomerAdd, ClerkNo, ClerkName, ItemNo, Descr iption, Qty, UnitPrice Think of this as the! baseline one large table Normalization: First Normal normal 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: OrderEssay.net

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