For the above given database STUDENT-PROJECT, can we perform the following operations?
Insert a student record with missing roll number value.
No, we cannot insert a student record with missing roll number value because RollNo is the primary key of the STUDENT table. Primary key values cannot be NULL as they uniquely identify each record.
Insert a student record with missing registration number value.
No, we cannot insert a student record with missing registration number value because Registration_ID is an alternate key in the STUDENT table. All alternate keys must have unique and non-NULL values.
Insert a project detail without submission-date.
Yes, we can insert a project detail without submission-date. SubmissionDate is not a primary key or alternate key in the PROJECT table, so it can accept NULL values unless a NOT NULL constraint is specified.
Insert a record with registration ID IP-101-19 and ProjectNo 206 in table PROJECT-ASSIGNED.
No, we cannot insert this record. The Registration ID IP-101-19 does not exist in the STUDENT table, and ProjectNo 206 does not exist in the PROJECT table. This would violate referential integrity constraints as both are foreign keys in PROJECT-ASSIGNED table referencing non-existent values in their parent tables.
Explanation
This question tests understanding of integrity constraints in databases. Parts (a) and (b) relate to entity integrity - primary keys and alternate keys cannot have NULL values. Part (c) tests understanding that non-key attributes can have NULL values. Part (d) tests referential integrity - foreign key values must exist in the referenced parent tables. The context shows Registration_ID values like IP-101-15, IP-104-15, CS-103-14, CS-101-14, CS-101-10 in STUDENT table and ProjectNo values 101-106 in PROJECT table, confirming that IP-101-19 and 206 don't exist.