Normalization - Normalization is the process of minimizing redundancy from a relation or set of relations. Redundancy in relation may cause insertion, deletion and updation anomalies., Functional Dependency - The functional dependency is a relationship that exists between two attributes. It typically exists between the primary key and non-key attribute within a table. X->Y The left side of FD is known as a determinant, the right side of the production is known as a dependent.  , Trivial functional dependency - A → B has trivial functional dependency if B is a subset of A, Non-trivial functional dependency - A → B has a non-trivial functional dependency if B is not a subset of A., 1NF - A relation is in 1NF if it contains an atomic value., 2NF - A relation will be in 2NF if it is in 1NF and all non-key attributes are fully functional dependent on the primary key., 3NF - A relation will be in 3NF if it is in 2NF and no transition dependency exists., States of Transaction - Active state,Partially committed,Committed,Failed state,Aborted, Problems with Concurrent Execution - 1)Lost Update Problems (W - W Conflict) ,2) Dirty Read Problems (W-R Conflict) ,3) Unrepeatable Read Problem (W-R Conflict)  , ACID Properties , Generalization - Generalization is like a bottom-up approach in which two or more entities of lower level combine to form a higher level entity if they have some attributes in common., Specialization - Specialization is a top-down approach, and it is opposite to Generalization. In specialization, one higher level entity can be broken down into two lower level entities.,

DBMS

podle
Tisk
Vložit

Výsledková tabule/Žebříček

Vizuální styl

Možnosti

Přepnout šablonu

Obnovit automatické uložení: ?