Question Type: Database Management System (DBMS) concepts
Step-by-step Solution:
- The question asks about the database language construct used to define the structure of a relation (table), delete relations (tables), and modify schemas (database structure).
- DDL (Data Definition Language) is specifically designed for defining the database structure. This includes creating, altering, and dropping database objects such as tables, indexes, and views.
- DML (Data Manipulation Language) is used for manipulating data *within* the database, such as inserting, updating, deleting, and querying data. It doesn't deal with defining the database structure itself.
- Integrity constraints define rules for ensuring data validity and consistency within a relation. They are part of the schema definition but don't encompass all schema-related operations like creating or dropping tables.
- Views are virtual tables based on the result-set of an SQL statement. They don't directly define the structure of the underlying base tables or allow for deletion of schemas.
Therefore, only DDL fulfills all the requirements mentioned in the question.
Why other options are incorrect:
- DML is for data manipulation, not structure definition.
- Integrity constraints are rules within the structure, not the structure definition itself.
- Views are derived tables; they don't define the base table structures.
Core Logic/Pattern: Understanding the functionalities of DDL and DML in database management is crucial. DDL is for defining database structure, whereas DML is for manipulating data within that structure.
Correct Answer: DDL (Data Definition Language)
Important Questions from Relational Model
Given the relational schema $R = (U,V,W, X, Y, Z)$ and the set of functional dependencies: $$\{U \rightarrow V, U \rightarrow W, WX \rightarrow Y, WX \rightarrow Z, V \rightarrow X\}$$ Which of the following functional dependencies can be derived from the above set?
- The ‘12 Rules for Relational Database’ were given by
- Which of the following statement(s) is/are FALSE in the context of Relational DBMS ?
I. Views in a database system are important because they help with access control by allowing users to see only a particular subset of the data in the database.
II. E-R diagrams are useful to logically model concepts.
III. An update anomaly is when it is not possible to store information unless some other, unrelated information is stored as well.
IV. SQL is a procedural language. - Let $R(A,B,C,D,E)$ be a relational schema with functional dependency set $F=\{A\rightarrow BC,\ CD\rightarrow E,\ E\rightarrow A\}$.
Which of the following statements is correct? Consider R (A,B,C,D,E) be relation with following dependencies:
C- >F, E- > A, EC- >D, A- >B. Which of the following is a key for R?
