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Define the Query optimisation
The query parser commonly generates a standard initial tree to correspond to an SQL query, with no doing any optimization. Such type of a canonical query tree denotes a relational algebra expression that is extremely inefficient if executed directly. A query commonly has many possible execution strategies, and the process of choosing a appropriate one for processing a query is termed as query optimization. The major guidelines that are applied throughout query optimization are:
a. Combine a cascade of selections
b. Combine a cascade of projections
c. Commute selection and projection
d. Commuting selection with join / cartesian product Commuting projection with join or cartesian product
e. Commute projection with set operations
f. Commute selection with set operations
Explain Alternate key? Alternate Key - All the candidate keys except primary key are known as alternate keys.
Define Boyce codd normal form A relation schema R is in BCNF with respect to a set F of functional dependencies if, for all functional dependencies in F + of the form.α ->β.
Project: Microsoft Access You have been asked by the ABC Tanning Salon to create a database that can be used to track the salon's customers. You are to create a table in Access
triggering
Problem 1. Create a PL/SQL program to insert data into student table and display the details of the student having Reg.No 1010 Writing a PL/SQL program to Insert data
10A.53 Code an Oracle Database trigger to enforce the constraint that an employee can never change his or her department. 10A.54 Code an Oracle Database trigger to allow the delet
Consistency: This property makes sure that a complete transaction implementation takes a database from one consistent state to another consistent state. If the transaction fails e
want a idea for final year project
Consider the subsequent relations for a database which keeps track of business trips of salespersons in a sales office: SALESPERSON (SSN, Name, start_year, Dept_no) TRIP (SSN, Fr
job scheduling for different cubes
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