Explanation:
A centralized database (sometimes abbreviated CDB) is a database that is located, stored, and maintained in a single location.
There are two types of secondary memories.
- RAM
- ROM
RAM:
- RAM stands for random access memory .
- It is expandable.
- we can do multiple things in it.
- Its erasable.
ROM
- ROM stands for read only memory.
- It is permanent .
- We can only read in it.
- Its permanent hence not removable.
Answer:
The Update statement in the DML is used for changing existing data in a table.
Explanation:
Their are following Sql statement in the DML.
Insert
This SQL statement is used for inserting data into the table.
select
This SQL statement is used for retrieving data from database
update
This SQL statement is used for updating data in a table.
delete
This SQL statement is used for delete data from database .
The "UPDATE" SQL statement in DML is used for Modify the data in the existing table .
Following are the syntax of Update SQL query
Update tablename
set column1=value1,column2=value2............column N=valueN
Where condition;
Example :Suppose we have student table and (rollno,name,age and add) are the field for that table we have to change the address of rollno 105
Then we use update query like that
UPDATE STUDENT
SET add='kalam nagar'
where rollno=105;
Answer:
Logical Expressions
Explanation:
The expressions that have logical statements which could be "true or false" are known as logical expressions. These types of expressions are also known as Boolean Expressions.
These expression are used in computer programming. The purpose of these expressions in programming is to make a decision that could be based on different conditions. These conditions could be true or false. This is the main reason that. logical expression makes best sense for values received in true or false.
