by admin | Jun 6, 2015 | sem3
Serializability Serializability is the classical concurrency scheme. It ensures that a schedule for executing concurrent transactions is equivalent to one that executes the transactions serially in some order. It assumes that all accesses to the database are done...
by admin | Jun 6, 2015 | sem3
Properties of Transactions A transaction can be defined as a group of tasks. A single task is the minimum processing unit which cannot be divided further. Let’s take an example of a simple transaction. Suppose a bank employee transfers Rs 500 from A’s account to...
by admin | Jun 6, 2015 | sem3
Dynamic Hashing The problem with static hashing is that it does not expand or shrink dynamically as the size of the database grows or shrinks. Dynamic hashing provides a mechanism in which data buckets are added and removed dynamically and on-demand. Dynamic hashing...
by admin | Jun 6, 2015 | sem3
Static Hashing STATIC HASHING In static hashing, when a search-key value is provided, the hash function always computes the same address. For example, if mod-4 hash function is used, then it shall generate only 5 values. The output address shall always be same for...
by admin | Jun 6, 2015 | sem3
B+ tree Index Files A B+ tree is a balanced binary search tree that follows a multi-level index format. The leaf nodes of a B+ tree denote actual data pointers. B+ tree ensures that all leaf nodes remain at the same height, thus balanced. Additionally, the leaf nodes...
by admin | Jun 6, 2015 | sem3
Hashing For a huge database structure, it can be almost next to impossible to search all the index values through all its level and then reach the destination data block to retrieve the desired data. Hashing is an effective technique to calculate the direct location...
