Question

Database Questions (Please help if you can)

1. For the same query task, different DBMSs may use different SQL statements.
2. 1. true         (b)         false

2. Given a table, any column of this table can be used as a key of the table.
3. 1. true         (b)         false

3. It is allowed to have multiple keys in a table.
4. 1. true         (b)         false

1. When we create a table in a DBMS, if we do not explicitly specify the database, the table can never be created the DBMS does n o t know where to put this table.
2. 1. true         (b)         false

5. Among the currently used database systems, there exists some database systems that do not require meta-data.
6. 1. true         (b)         false

5. In any table, there must be an attribute that is used as the primary key.
6. 1. true         (b)         false

9. It is NOT allowed to share elements in different schemas.
10. 1. true         (b)         false

11. If a table has a secondary key, it always uses a single attribute as a secondary key.
12. 1. true         (b)         false

12. When we define a table, if we know that the rows do NOT have distinct values with respect to any attribute, then it is impossible to define a primary key for this table.
13. 1. true         (b)         false

13. In a relation, attributes listed in a tuple are considered to be ordered.
14. 1. true         (b)         false

14. In a relation, tuples are considered to be ordered.
15. 1. true         (b)         false

18. There must be an order defined for any attribute in a SQL table.
19. 1. true         (b)         false

19. When you design a table in SQL, it is required that you have at least one secondary key.

1. true         (b)         false

Answer 1

According to HomeworkLib policy we answer the first four but I answer first seven question for you.

Answer 1) false
Explanation
SQL statements are similiar in all DBMS

Answer 2) false
Explanation
Only that column can be a key of table which contains unique value and not null values.

Answer 3) false
Explanation
In a table , their is only one key. But we can combine more than one column as a key column.

Answer 4) true
Explanation
Without a database name a table cannot be created because the database signifies where to store the table.

Answer 5) false
Explanation
Meta-data is must for the database. Without meta-data a data from a table cannot be queried.

Answer 6) false
Explanation
A table can be created without primary key.

Answer 7) false
Explanation
We can share elements between different schemas by grant statement in SQL.