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

さんの投稿です
印刷
埋め込み

リーダーボード

表示スタイル

オプション

テンプレートを切り替える

自動保存: を復元しますか?