Informatics Practices
Assertion (A): A database can have only one table.
Reasoning (R): If a piece of data is stored in two places in a database, then it leads to wastage of storage space.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Answer
A is false but R is true.
Explanation
A database can have multiple tables. Data redundancy, which occurs when the same data is repeated in multiple places within a database, leads to wastage of storage space. A DBMS eliminates data redundancy by integrating files, ensuring that multiple copies of the same data are not stored.
Related Questions
Assertion (A): The number of attributes or columns in a relation is called the degree of the relation.
Reasoning (R): The number of tuples or records in a relation is called the cardinality of the relation.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Assertion (A): Each table must have one primary key.
Reasoning (R): Primary key is a set of one or more attributes that uniquely identifies a tuple in a relation.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Assertion (A): A database constraint can be added or removed any time in/from the database tables.
Reasoning (R): Alter table command is used to change the structure of the table.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Assertion (A): SQL has efficient mechanisms to retrieve data stored in multiple tables in a MySQL database.
Reasoning (R): The SQL statement CREATE is used to retrieve data from the tables in a database and is also called query statement.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.