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).
Forward Declarations The PL/SQL needs that you declare an identifier before using it. And hence, you should declare a subprogram before calling it. For illustration, the decla
Keyword and Parameter Description: table_reference: This specifies a table or view that should be accessible when you execute the DELETE statement, and for that you must
At times, customers make mistakes in submitting their orders and call to cancel the order. Brewbean’s wants to create a trigger that automatically updates the stock level of all pr
Functions The function is a subprogram that calculates a value. The Functions and procedures are structured similar, except that the functions have a RETURN clause. You can
what is the use of declare keyword
First Step at defining type SID in SQL CREATE TYPE SID AS ( C VARCHAR(5) ) ; Explanation: TYPE SID announces that a type named SID is being defined to the syst
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
query to Find the account numbers of all customers whose balance is more than 10,000 $
a. Create a table odetails_new. It has all the attributes of odetails and an additional column called cost, whose values are the product of the quantity and price of the part bein
I need SQL Data Base Project Description: Network SQL database and SQL Setup two 4 workstation Skills required are Data Entry, MySQL, SQL
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