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!
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.
Using LOCK TABLE You use the LOCK TABLE statement to lock the whole database tables in the specified lock mode so that you can share or deny the access to them. For illustrati
Left and Right Joins LEFT OUTER JOIN can be used when you want to retrieve the data from the main table (table1) even if there is no match in other tables (table_2, table_3...
Example of Table Literal - SQL Example: A Table Literal (correct version) VALUES ('S1', 'C1', 'Anne'), ('S1', 'C2', 'Anne'), ('S2', 'C1', 'Boris'), ('S3', 'C3'
Parameter and Keyword Description: dynamic_string: This is a string variable, literal, or expression which represents a SQL statement or the PL/SQL block. define_vari
Fetching from a Cursor Variable The FETCH statement retrieve rows one at a time from the product set of a multi-row query. The syntax for the same is as shown: FETCH {curso
Question: a) Given the following relation: Location(loc_id, bldg_code, room, capacity) The underlined field is a primary key. (i) Write a PL/SQL program using the impl
Question: (a) In the context of database security explain how the following database features help to enforce security in the database system: (i) Authorisation (ii) Access
Operators on Tables and Rows Row Extraction TUPLE FROM r, SQL has row subqueries. These are just like scalar subqueries except that they may specify more than one column.
ALTER TABLE bb_basketitem ADD CONSTRAINT bitems_qty_ck CHECK (quantity BEGIN INSERT INTO bb_basketitem VALUES (88,8,10.8,21,16,2,3); END; Brewbean’s wants to add a check
Procedures The procedure is a subprogram which can take parameters and be invoked. Normally, you can use a procedure to perform an action. The procedure has 2 sections: the spe
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: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd