Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Example of WHEN or THEN Constraints
A concrete example showing how SQL supports WHEN/THEN constraints
CREATE TABLE SAL_HISTORY (EmpNo CHAR (6),
Salary INTEGER NOT NULL,
From DATE
To DATE
PERIOD FOR During (From, To),
PRIMARY KEY (EmpNo, During WITHOUT OVERLAPS)
) ;
The PERIOD FOR specification states that the From and To values in each row denote a time interval (called a period because SQL uses the term "interval" for something else). The From values are treated as closed bounds, the To values as open bounds, so a given row in SAL_HISTORY indicates that an employee was paid a certain salary from the given From date up to but not including the given To date. The specification implies the column constraint NOT NULL NOT DEFERRABLE ENFORCED for each of columns From and To. During WITHOUT OVERLAPS, which, if required, must appear as the last element of the key, specifies that if the same EmpNo value appears in two distinct rows of SAL_HISTORY, then the From and To values in those rows must denote During periods that do not overlap (have no date in common).
Project Description: I want a small relational database to be built. I want the database to have the subsequent information tables: Employee Information Document storage
V ariables and Constants in PL/SQL The PL/SQL permits you to declare constants and variables, and then use them in SQL and procedural statements anywhere in the expression. Th
Overloading The PL/SQL overloads the subprogram names. That is, you can use similar name for few different subprograms as long as their formal parameters differ in the number
Parameter Modes: You do not require to specify a parameter mode for the input bind arguments (those used, for illustration, in the WHERE clause) as the mode defaults to IN. Th
Conditionals - SQL At first sight SQL does not appear to have a single operator for expressing logical implication. In this respect it would be in common with most programming
Parameter and Keyword Description: cursor_name: This identifies an explicit cursor formerly declared within the present scope. cursor_variable_name: These identif
Write a query to find academics that are authors and that have only ever coauthored papers with authors from institutes in the same state as their own. List their academic number,
1. a. Write a trigger that fires when a part's price is updated. The trigger will write a record into a table called PriceUpdates. The record should contain the information of
What are 3 good practices of modeling and/or implementing data warehouses?
Data Types in SQL - Decimal DECIMAL, NUMERIC, REAL, FLOAT and various other terms for various sets of rational numbers. When these key words are specified for the declared typ
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd