databases Online Quiz - 120
|Description: databases Online Quiz - 120|
|Number of Questions: 20|
|Created by: Aliensbrain Bot|
DB2 WITH HOLD option What does WITH HOLD option do ?
If the value is null in order to place a value in it the function used is
Unique numbers can be assigned to columns in a database using
A table T1 having 100 rows is joined with a table T2 with 50 rows without specifying the joined column in the where clause then result will have
Which of the following is FALSE about a ALTER TABLE command of SQL?
Which one of the following does not help to maintain referential integrity?
To answer this question, we need to understand the concept of referential integrity.
Referential integrity is a database constraint that ensures the relationships between tables are maintained correctly. It ensures that foreign key values in a table match primary key values in another table, or are null.
Let's go through each option to understand why it does or does not help to maintain referential integrity:
Option A) Unique constraints - This option is incorrect because unique constraints help to maintain referential integrity. They ensure that no two rows in a table have the same values in the specified columns.
Option B) Primary keys - This option is correct because primary keys help to maintain referential integrity. They uniquely identify each record in a table and are used as foreign keys in other tables to establish relationships.
Option C) Cascading actions - This option is incorrect because cascading actions help to maintain referential integrity. They define what happens to related records in other tables when the referenced record is updated or deleted.
Option D) Foreign keys - This option is incorrect because foreign keys help to maintain referential integrity. They establish relationships between tables by referencing the primary key of another table.
Based on the explanations above, the correct answer is A) Unique constraints. Unique constraints do not directly help to maintain referential integrity; instead, they ensure that no duplicate values are present in specified columns.
A control file contain information about
Log switch is
Which statement represents a default characteristic of the database if a database is created using the database creation assistant?
What is a cluster Key
What is Privilidge auditing
What is a Two-Phase Commit
When attempting to connect to an instance that is down, which Oracle Net feature or component facilitates automatic connect-time fail-over to another instance for the user?
Which type of view is implemented as a subquery embedded in the FROM clause of a SELECT statement and is identified by an alias?