Exercise Answers — tap any question to reveal the answer and explanation.
1. Which of the following actions can be performed once the tables are created in a database?
Answer: (d) All of the above
Explanation: Once a table is created, fields can still be added, the table can be renamed, and it can also be deleted.
2. Which of the following is checked by a DBMS?
Answer: (c) Both (a) and (b)
Explanation: A DBMS is designed to check and control both data redundancy and data inconsistency.
3. Which of the following is required to set a relationship between the two tables?
Answer: (b) Both the tables must have a common field
Explanation: A relationship between two tables can only be set when they share a common field, usually the primary key of one and the corresponding foreign key of the other.
4. If a record is added in a master table, which of the following is NOT true for transaction table?
Answer: (b) The corresponding record in transaction table can only be entered once
Explanation: In a one-to-many relationship, a single master record can have several corresponding records entered in the transaction table, so this statement is not true.
5. Which type of relationship exists between a student and the subjects studied by him/her?
Answer: (b) One-to-many
Explanation: A student record is entered once in the master table, while subjects are linked as repeating foreign-key values in the transaction table — the same one-master/many-transaction pattern used for the teacher–student and category–event examples in the chapter.
6. Consider the following tables. Which type of relationship can be established between the two tables?
| Table 1: Item | Table 2: Item_Category |
|---|---|
| Item_Code | Category_Code |
| Item_Name | Cat_Name |
| Price | Item_Code |
| Qty | Cat_Disc |
| Category_Code |
Answer: (b) One-to-many
Explanation: Category_Code is the primary key in Item_Category (master table, one record per category) and appears as a foreign key in Item (transaction table). One category can be linked to many items.
7. Which of the following menus contains the Relationship option?
Answer: (c) Tools
Explanation: The Relationships option, used to set up relations between tables, is found in the Tools menu.
8. The list of tables to be added is displayed in the __________ dialog box in the Relationship Screen.
Answer: (a) Add Tables
Explanation: The Add Tables dialog box lists all the tables in the database, from which the required tables can be added to the Relationship Design window.
9. In the relationship design screen, the relationship between the two tables is done using __________ operation.
Answer: (c) Drag and Drop
Explanation: The common field of one table is dragged and dropped onto the corresponding field of the other table to create the relationship.
10. Which of the following is NOT an option that can be used to maintain referential integrity in a database?
Answer: (d) Set Value
Explanation: The valid referential integrity options are No action, Update cascade, Set NULL and Set default — "Set Value" is not one of them.
Answer: False
Explanation: Redundancy should be avoided, not preferred, in a database.
Answer: True
Explanation: Repeating a record for the same entity leads to redundancy, which a well-designed table avoids.
Answer: False
Explanation: A field can be left blank (null), so it does not always hold a single fixed value in every case.
Answer: False
Explanation: Editing a table's structure does not affect the records already entered in it.
Answer: True
Explanation: A transaction record can only refer to a master record that already exists, so the master record must be entered first.
Answer: True
Explanation: This is the defining feature of a one-to-many relationship.
Answer: False
Explanation: The Relationship option is present in the Tools menu, not the Windows menu.
Answer: False
Explanation: Referential integrity is maintained automatically by the DBMS, not manually by the user.
Answer: True
Explanation: A common field (primary key–foreign key pair) is the basic requirement for setting up any relationship.
Answer: False
Explanation: The outcome depends on the referential integrity option chosen — "No action" prevents deletion, "Set NULL"/"Set default" don't delete the transaction record; only "Update cascade" deletes it.
Answer: Design
Answer: Common field
Answer: One-to-One
Answer: One-to-Many
Answer: Transaction; Master
Answer: Referential integrity
Answer: Relationships
Answer: DBMS
Answer: Many-to-many
Answer: Relationship (Design)
Answer:
Answer: Redundancy and inconsistency are controlled by setting up a relationship between two tables through a common field — the primary key of the master table and the corresponding foreign key of the transaction table.
Example: In a Student_Details (master) and Student_Result (transaction) database, Admission No is the primary key in Student_Details and a foreign key in Student_Result. A student's personal details are stored only once in Student_Details, and Student_Result simply references the Admission No, so the same details aren't repeated or entered inconsistently across tables.
Answer: Referential integrity is the principle that no unmatched foreign key values should exist in a database — i.e., every foreign key value in a transaction table must correspond to an existing primary key value in its master table. It is maintained by the DBMS (e.g., LibreOffice Base).
Answer:
| One-to-One | One-to-Many |
|---|---|
| One specific record in the master table has exactly one corresponding record in the transaction table. | One specific record in the master table has more than one corresponding record in the transaction table. |
| Example: a student and their admission number, or a person and their stadium entry ticket. | Example: one teacher teaching multiple students/classes, or one event category linked to multiple events. |
Answer: In a many-to-many relationship, multiple records in the master table correspond to multiple records in the transaction table — used when a record needs to be saved more than once in both related tables.
Example: A teacher may hold multiple responsibilities (examination in-charge, discipline in-charge, etc.), and each responsibility may involve multiple activities/students; similarly, a shopkeeper sells multiple products to multiple customers, so the relationship between products and customers is many-to-many.