This is a theory question about database constraints and referential integrity. Each sub-part asks whether a particular insert operation is permissible given the schema.

To answer, we need to infer the constraints from the structure and data:

• STUDENT: Roll No appears to be the primary key (unique, identifies each student). Registration_ID is also unique and serves as a foreign key target.
• PROJECT: ProjectNo is the primary key.
• PROJECT_ASSIGNED: This is a junction table linking students to projects. Registration_ID references STUDENT, and ProjectNo references PROJECT (both are foreign keys). Together they likely form a composite primary key.

Now evaluate each operation:

1. Insert a student record with missing roll number value. A primary key cannot be NULL. The Roll No column uniquely identifies each student, so every student record must have a roll number. Attempting to insert a row with a missing (NULL) Roll No violates the primary key constraint. Not allowed.
2. Insert a student record with missing registration number value. Looking at the data, every student has a Registration_ID, and it appears in PROJECT_ASSIGNED as a foreign key. However, Registration_ID in STUDENT is not necessarily the primary key (that role belongs to Roll No). If Registration_ID is defined as NOT NULL or UNIQUE, a missing value would be rejected. But if it is simply a regular attribute (nullable), the insert might succeed—though in practice, for a student-project system, registration IDs are typically mandatory. The safer interpretation, given that every existing row has a Registration_ID and it is used as a foreign key elsewhere, is that it is required (NOT NULL). Not allowed (assuming NOT NULL constraint).
3. Insert a project detail without submission-date. …

Understanding the Schema Constraints

Before we can answer what operations are allowed, we need to infer the logical constraints from the given tables. While the question doesn't explicitly state PRIMARY KEY or FOREIGN KEY declarations, the structure and data reveal them:

STUDENT table:

• Roll No appears to be the primary key (unique identifier for each student)
• Registration_ID is a unique identifier (each student has exactly one; it links to PROJECT_ASSIGNED)

PROJECT table:

• ProjectNo is the primary key (unique identifier for each project)

PROJECT_ASSIGNED table:

• This is a junction/linking table connecting students to projects
• Registration_ID is a foreign key referencing STUDENT
• ProjectNo is a foreign key referencing PROJECT
• Together they likely form a composite primary key (one student can be assigned one project)

Now let's examine each operation:

(a) Insert a student record with missing roll number value

Can we do this? No.

Roll No is the primary key of the STUDENT table. A primary key has two fundamental properties:

1. Uniqueness — no two rows can have the same value
2. NOT NULL — every row must have a value

A missing (NULL) roll number violates the second property. The database will reject this insertion with a constraint violation error.

-- This will FAIL
INSERT INTO STUDENT (Roll_No, Name, Class, Section, Registration_ID)
VALUES (NULL, 'Rahul', 'XI', '1', 'IP-102-15');
-- Error: PRIMARY KEY constraint violation - NULL not allowed

(b) Insert a student record with missing registration number value

Can we do this? It depends on the constraint definition, but most likely No.

Looking at the data, every student has a Registration_ID, and PROJECT_ASSIGNED uses it as a foreign key. This suggests two possible scenarios:

Scenario 1: Registration_ID is defined as UNIQUE NOT NULL

• The insertion would fail because NULL violates the NOT NULL constraint

Scenario 2: Registration_ID allows NULL but is UNIQUE

• The insertion would succeed — the student exists but hasn't been assigned a project yet

However, given that Registration_ID appears to be a student identifier (like an enrollment number) rather than just a link to projects, it's most likely defined as NOT NULL. A student without a registration ID doesn't make practical sense in an academic system.

-- This will likely FAIL
INSERT INTO STUDENT (Roll_No, Name, Class, Section, Registration_ID)
VALUES (13, 'Rahul', 'XI', '1', NULL);
-- Error: NOT NULL constraint violation (if Registration_ID is NOT NULL)

Most probable answer: No — the registration ID is a required attribute.

(c) Insert a project detail without submission-date

Can we do this? Yes, most likely.

SubmissionDate is not the primary key of PROJECT (that's ProjectNo). Unless explicitly defined with a NOT NULL constraint, regular columns in SQL can accept NULL values.

A NULL submission date could represent:

• A project that hasn't been submitted yet
• A project with an unknown/unrecorded submission date

-- This will likely SUCCEED
INSERT INTO PROJECT (ProjectNo, PName, SubmissionDate)
VALUES (107, 'Hospital Database', NULL);
-- Success: NULL is allowed in non-key columns unless explicitly restricted

(d) Insert a record with registration ID IP-101-19 and ProjectNo 206 in table PROJECT_ASSIGNED

Can we do this? No.

PROJECT_ASSIGNED has two foreign key constraints: …