Answer:
Giving that: The following is a sequence of undo-log records written by 2 transactions T and U:
< START T >;
< T,A,10 >;
< START U >;
< U, B, 20 >;
< T, C, 30 >;
< U, D, 40 >;
< Commit U >;
< T, E, 50 >;
< Commit T >;
1. < START U >
Recovery action in this case will be undo(-1) and undo(0). All restored to its original Value
log records < T, A, 10 >, < T, abort >; as written out
2. < T, E, 50 >
Recovery action in this case will be undo(8) and redo(0). A and C is restored to its original value, B and D are set to 20 and 40
log records <T, C, 30 >, < T, A, 10 >, < T, abort > are written out
3. < Commit T >
Recovery action in this case will be redo(7) and redo(4). A and C are set to 10 and 30, B and D are set to 20 and 40
Answer:
There are two customers in the PostalCode.
SQL statement for select all the fields and the rows from the Customers table where PostalCode is 44000.
SELECT * FROM Customers WHERE PostalCode = "44000";
Explanation:
The SELECT statement retrieve zero or more than one row from 1 or more than one the database tables or the database views.
In most of the applications, the SELECT query is most commonly used for DQL(Data Query Language) command.
SQL is the declarative programming language and the SELECT statement specifies the result set, but they do not specifies how to calculate it.
Answer:
See Explanation
Explanation:
I'll assume the question is about the use of constants in QBasic because consonants do not have any special function or usage in QBasic.
In simple terms: In QBasic, constants are used to represent elements that do not change in value during program execution.
Take for instance, you intend to use 
in your program.
Its value is 
So, 3.142 will always be a constant in your program. One of the ways it can be used in a program is:
10 LET PI = 3.142
<em>The above represents a numeric constant. QBasic also have string constants.</em>
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