Already have an account? Get multiple benefits of using own account!
Login in your account..!
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!
Effects of NULL for union - SQL
The treatment of NULL in invocations of EXCEPT is as for UNION. This is different from its treatment in those of NOT IN and quantified comparisons. In the case of t1 EXCEPT t2, row r of t1 appears in the result if and only if there does not exist a row s in t2 such that r IS NOT DISTINCT FROM s evaluates to TRUE. Note that x NOT IN (t) evaluates to UNKNOWN whenever x = x does, including in particular the case where x IS NULL evaluates to TRUE because every field of the row x is the null value. Recall that when the condition given in a WHERE clause evaluates to UNKNOWN for row r, then r does not appear in the result.
The Package Specification The package specifications contain the public declarations. The scopes of these declarations are local to your database representation and global to t
Using the Collection Methods The collection methods below help to generalize the code and make collections easier to use and also make your applications easier to maintain:
THEORY OF BIOGENESIS - This theory explains that the existing living organisms originated from pre-existing living beings not from non living entities. This concept of or
Map and Order Methods: The values of the scalar datatype like CHAR or REAL have a predefined order that allows them to be compared. While, the instances of an object type has
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
Using SAVEPOINT The SAVEPOINT names and marks the present point in the processing of a transaction. Used with the ROLLBACK TO statement, the savepoints undo parts of a transac
Relational Algebra - SQL It describes some operators, that together constitute an algebra that is not only relationally complete but also irreducibly so (very nearly- apart f
ORIGIN OF EARTH - BIG-BAN G HYPOTHESIS - Origin of life is linked to origin of earth. Cosmos, the Universe originated 10-20 billion years ago by Big Bang (thermonu
Initializing Records The illustration below shows that you can initialize a record in its type definition. Whenever you declare a record of the type TimeRec, its 3 fields supp
Iterative Control: LOOP Statements The LOOP statement executes a series of statements multiple times. There are 3 forms of LOOP statements: LOOP, WHILE-LOOP, & FOR-LOOP. LOOP
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!
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd