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.
How do I display usernames for students from a student table, assigning each student a username initials001 (initials is the actual student initials), and if the students initials
Understanding Nested Tables Within the database, the nested tables can be considered as one-column database tables. The Oracle stores the rows of a nested table in no specific o
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
LOB Types The large object (LOB) datatypes like BFILE, BLOB, CLOB, and NCLOB store the blocks of unstructured data (like graphic images, text, video clips, and sound waveforms)
Write an anonymous block that contains a PL/SQL procedure. The procedure takes two input parameter: oldZip and newZip, and it updates the zipcodes table by replacing all oldZip wit
THEO R Y OF ETERNITY OF LIFE (PRAYER - 1880) - The theory of eternity of life, also called the steady-state theory , states that life has ever been in existence as at presen
Explicit Cursor Attributes The cursor variable or each cursor has four attributes: %FOUND, %ISOPEN, %ROWCOUNT, and %NOTFOUND. When appended to the cursor or cursor variable, th
Literals A literal is an explicit numeric, string, character, or Boolean value not represented by an identifier. Numeric literal 147 and the Boolean literal FALSE are some of
Managing Cursors The PL/SQL uses 2 types of cursors: implicit and explicit. The PL/SQL declares a cursor implicitly for all the SQL data manipulation statements, including th
Updating Tables in SQL The topic of updating by describing the assignment operator, ":=" in Tutorial D. SQL uses a different syntax for assignment, using the key word SET and
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