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Question:(a) The objective of query optimization is to choose the most efficient strategy for implementing a given relational query, thereby improving the system performance. One of the stages of query optimization is to convert the internal form into equivalent and more efficient canonical form, using well-defined transformation rules. Two rules of the transformation rules is given below:Rule 1 - Transform a sequence of restrictions against a given relation into a single (ANDed) restriction.Rule 2 - Transform a restriction of a projection into a projection of a restriction.(i) Explain what is meant by each of the above rules.(ii) Using the relational schema given in Appendix, provide example of each of the above rules.(b) Refer to the relational schema given in Appendix.Assuming that: The Employee relation contains 1000 records among which 300 employee are assigned to departments located in the United States.- The Department relation contains 30 records among which 20 departments are located in United States- The Location relation contains 20 records among which 5 are situated in the United States.(i) Express the following query in SQL:"find the employee Last names and the department names who are working in United States (Location.country_id = US)(ii) Choose two possible methods to evaluate the query, and use the relational algebra to formulate clearly all the steps required in the evaluation. For each method, calculate the number of tuples for all the intermediate relations (namely, size of the intermediate relations) required for each step.
Using Pragma RESTRICT_REFERENCES: The function called from the SQL statements should obey certain rules meant to control the side effects. To check for violation of the rules,
Parameter and Keyword Description: cursor_name: This identifies an explicit cursor formerly declared within the present scope. cursor_variable_name: These identif
Tautology - Equivalences Rules: If there Tautologies are not all the time as much easy to note as the one above so than we can use these truth tables to be definite that a sta
Manipulating Collections Within PL/SQL, the collections add procedural power and flexibility. The biggest benefit is that your program can compute subscripts to process the spec
The accuracy of product table data is critical and the Brwebean's. owner wants to have an audit file that contains information regarding all DML activity on the BB_PRODUCT table. T
Example of Table Literal - SQL Example: A Table Literal (correct version) VALUES ('S1', 'C1', 'Anne'), ('S1', 'C2', 'Anne'), ('S2', 'C1', 'Boris'), ('S3', 'C3'
Create a procedure named STATUS_SHIP_SP that allows a company to employee in the Shipping Department to update the status of an order to add shipping information. The BB_BASKETSTAT
Example of Alternative formulation as a table constraint Example: Alternative formulation as a table constraint ALTER TABLE EXAM_MARK ADD CONSTRAINT Must_be_enrolled_to_
GOTO Statement The GOTO statement branches to a label unconditionally. The label must be exclusive within its scope and should precede an executable statement or a PL/SQL block.
Declaring Cursor Variables Once a REF CURSOR type is define by you, and then you can declare the cursor variables of that type in any PL/SQL block or subprogram. In the exampl
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