Lossless Dependency Preserving 3NF decomposition Algorithm 1

The minimal cover of F is given 1. Search for dependencies in F-having the same attribute set on the left hand side A: A->B1, A->B2, A->B3, …, A->Bk And construct relation as (A, B1, B2, B3,…, Bk) 2. Construct a relation with remainder attributes. 3. In case none of the relations has a candidate key, ...

Wait-die and Wound-wait Schemes 8

Wait-die scheme: It is a non-preemptive technique for deadlock prevention. When transaction Ti requests a data item currently held by Tj, Ti is allowed to wait only if it has a timestamp smaller than that of Tj (That is Ti is older than Tj), otherwise Ti is rolled back (dies) For example: Suppose that transaction T22, T23, T24 have time-stamps 5, 10 and ...

Database Connection Pooling 2

In software engineering, a connection pool is a cache of database connections maintained so that the connections can be reused when future requests to the database are required. Connection pools are used to enhance the performance of executing commands on a database. Opening and maintaining a database connection for each user, especially requests made to ...