Normalizing Database Tables
Added on 2019-09-26
6 Pages818 Words226 Views
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Part 1:CharityIDCharityNameCharityLocationPOCNamePOCIDTelExtn.Customer IDCustomer NameDateContribution StartedNoofMonthDatePlacesExpectedContribution End1st NF:Database normalization technique is used to maintain minimum number of attributes with minimum data redundancy. First normal form demands that there should be atomic value in each cell of each column. It also ensures there are no repeating groups.CharityDonation (CharityID, CharityName, CharityLocation, POCName, POCID, TelExtn, CustomerID, CustomerFirstName, CustomerLastName, StartDate, NumberOfMonths, DatePlaced, ExpectedEndDate)2nd NF:According to Second Normal Form there must not be any partial dependency of any column on primary key. In other words no non-prime attribute is dependent on the proper subset of any candidate key of table.Charity (CharityID, CharityName, CharityLocation) POC (POCID, POCName, TelExtn) Customer (CustomerID, FirstName, LastName) Donations (CustomerID, DatePlaced, StartDate, NumberOfMonths, ExpectedEndDate)
3rd NF:There are two rules followed in Third Normal FormTable must be in Second Normal FormTransitive functional dependency of non- pirme attribute on any super key should be removed.An attribute that is not part of any candidate key is known as non-prime attribute.So according to these rules, the tables are already in 3rd NF because each of the attributes is dependent on the primary key and here we just need to relate tables to one another.Contributions (DonationID, CustomerID, CharityID, POCID) Charity (CharityID, CharityName, CharityLocation) POC (POCID, POCName, TelExtn) Customer (CustomerID, FirstName, LastName) Donations (DonationID, DatePlaced, StartDate, NumberOfMonths, ExpectedEndDate)Boyce- Codd Normal FormHere is DatePlaced in the donations table, the datePlaced column is depend on Contribution table.Contributions (DonationID, CustomerID, CharityID, POCID,DatePlaced) Charity (CharityID, CharityName, CharityLocation) POC (POCID, POCName, TelExtn) Customer (CustomerID, FirstName, LastName) Donations (DonationID, StartDate, NumberOfMonths, ExpectedEndDate)
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