State the steps involved in query processing. Why is the query optimization needed?

Query processing refers to the range of activities involved in extracting data from a database. The activities include translation of queries in high-level database languages into expressions that can be used at the physical level of the file system,

Super Admin

added 3 years ago

Explain how to reduce a relationship set of an E-R diagram into relational schema.

There are several processes and algorithms available to convert ER Diagrams into Relational Schema. Some of them are automated and some of them are manual. We may focus here on the mapping diagram contents to relational basics.

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added 3 years ago

Consider the following relations and write down expressions for the following queries:

EMP (eid, ename, age, address, salary)

Works (eid, did, hours)

Dept (did, dname, managerid)

1. List the names of employees who work for the ‘Research’ department for 8 hours using Relational Algebra.
2. List the name and address of all employees with department number 5 using Relational Calculus.
3. Find the managerid of managers who manage only departments with budgets greater than 1 lac using SQL.
4. Find the employee who has highest salary using SQL.

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added 3 years ago

What is the need for normalization? Explain 2nd and 3rd normal form with example.

Consider the following relation:

EMP_PROJ { SSn, Pnumber, Hours, Ename, Pname, Plocation}

Assume { SSn, Pnumber} as primary key.

The dependencies are {SSn, Pnumber}→ Hours; SSn →Ename; Pnumber → {Pname, Plocation}.

Normalize the above relation into 2NF.

Develop a good description of the data, its relationships and constraints Produce a stable set of relations that Is a faithful model of the enterprise Is highly flexible

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added 3 years ago

Let R (ABCDE) be a relation schema and consider the following functional dependencies

F = { AB→ E, AD→B, B→ C, C→D}.

Find out the candidate key.

 

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added 3 years ago

Write short notes: B tree

A B-tree is a tree structure where every node corresponds to a disk page and which satisfies the following properties:

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added 3 years ago

Draw a minimum heap tree from the below list :

       12, 11, 7, 3, 10, – 5, 0, 9, 2

Now do the heap sort operation over the heap tree which you have formed. Write the insertion sort algorithm.

for( i=1; i<n;i++) { temp=a[i];

Demo Teacher

added 2 years ago

What is a minimum spanning tree ? Describe Huffman’s Algorithm.   

A spanning tree of a graph is just a subgraph that contains all the vertices and is a tree. Huffman’s algorithm is a method for building an extended binary tree with a minimum weighted path length from a set of given weights.

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added 2 years ago

What are the differences between AVL Tree & Binary Search Tree ?

A binary search tree (BST) is a binary tree data structure which has the following properties: ->each node has a value;

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added 2 years ago

Find the time complexity of Binary Search Algorithm. 

In binary search each step of the algorithm divides the list of items being searched in half of the list. So we can say that

Demo Teacher

added 2 years ago