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!
Row Counterparts of Table Operators
SQL does not have counterparts tuple rename, tuple projection, tuple extension, tuple join and tuple compose. To obtain the same effects as these operators on row r, one has first to derive the table t consisting of just r, then apply the SQL counterpart of the corresponding relational operator on t, putting parentheses around the table expression so that, so long as the context is appropriate, it becomes a row subquery. For example, if r has fields named a, b, and c, we can simulate a tuple renaming of a tuple projection to obtain the row consisting of just a and b, with b renamed to x, by (SELECT a, x FROM VALUES (r) AS t(a, x, c)).
The snag here is that the columns of a VALUES expression have implementation-dependent names, so we cannot rely on the field names of r being propagated to the table. We therefore have to specify the names in parentheses after the range variable name, t. At least that gives us the slight short cut of renaming b as x on the fly, so to speak.
Project Description: I want to write some SQL statements. The things I need are between pages 5-7. The only problem is that i want it till tomorrow. Skills required is SQL
Parameter and Keyword Description: cursor_variable_name: This identifies a cursor variable or the parameter formerly declared within the present scope. host_cursor_va
Some Varray Examples In SQL Plus, assume that you define an object type Project, as described below: SQL> CREATE TYPE Project AS OBJECT ( 2 project_no NUMBER(2), 3 title VARCHA
Using ROLLBACK The ROLLBACK statements end the present transaction and undo any change made during the transaction. The Rolling back is helpful for two reasons. Firstly, if yo
Updating Objects: To change the attributes of objects in an object table, you can use the UPDATE statement, as the illustration below shows: BEGIN UPDATE persons p SET p
How Bulk Binds Improve Performance The assigning of values to the PL/SQL variables in SQL statements is known as binding. The binding of the whole collection at once is know
Overloading: Similar to packaged subprograms, methods of the same type can be overloaded. That is, you can use similar name for various methods if their formal parameters diff
Using PRIOR and NEXT The PRIOR(n) returns the index number that precede index n in a collection. The NEXT(n) returns the index number which succeed the index n. If n has no pr
Using research notes and Oracle documentation plan and execute an upgrade of an installation of Oracle 10g to Oracle 11g release 1. To do this you must show in screen shots and wri
Anatomy of a Command Figure, showing a simple SQL command, is almost identical to its counterpart in the theory book. The only difference arises from the fact that SQL uses a
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