1Z0-006 Database Concepts & Terminology 4 — Questions and Answers
Question 1: What does DDL stand for in the context of SQL?
- Data Distribution Language
- Data Definition Language (Correct answer)
- Dynamic Data Loading
- Database Design Layer
Correct answer: Data Definition Language
DDL (Data Definition Language) includes SQL statements like CREATE, ALTER, and DROP that define or modify the structure of database objects.
Question 2: Which SQL sublanguage includes the INSERT, UPDATE, and DELETE statements?
- DDL
- DCL
- DML (Correct answer)
- TCL
Correct answer: DML
DML (Data Manipulation Language) consists of statements that add, modify, or remove data rows within existing database tables.
Question 3: In an Entity-Relationship (ER) diagram, a weak entity is one that:
- Has fewer than three attributes
- Cannot be uniquely identified without the primary key of another entity (Correct answer)
- Does not participate in any relationships
- Contains only optional attributes
Correct answer: Cannot be uniquely identified without the primary key of another entity
A weak entity lacks a primary key of its own and depends on a related strong entity's primary key (called the owner entity) for its unique identification.
Question 4: What is the purpose of an index in a relational database?
- To enforce referential integrity between tables
- To speed up data retrieval operations on a table (Correct answer)
- To define the structure of a table
- To log all transactions for auditing purposes
Correct answer: To speed up data retrieval operations on a table
An index is a data structure that provides a fast lookup path to rows in a table, significantly improving query performance at the cost of additional storage and write overhead.
Question 5: Which concept refers to hiding the internal complexity of a database from end users and applications?
- Normalization
- Abstraction (Correct answer)
- Replication
- Partitioning
Correct answer: Abstraction
Data abstraction allows users and applications to interact with data at a high level without needing to know how it is physically stored or organized internally.
Question 6: A 'composite key' is a primary key that:
- Contains encrypted values for security
- Consists of two or more columns combined to uniquely identify a row (Correct answer)
- References columns from two different tables
- Is automatically generated by the database system
Correct answer: Consists of two or more columns combined to uniquely identify a row
A composite key uses a combination of two or more columns whose combined values are unique across all rows, used when no single column alone can serve as the primary key.
Question 7: What is a 'stored procedure' in a database?
- A method for physically storing data on disk
- A precompiled set of SQL statements stored in the database that can be called by name (Correct answer)
- A trigger that fires automatically on data changes
- A view that stores data results permanently
Correct answer: A precompiled set of SQL statements stored in the database that can be called by name
A stored procedure is a named, precompiled collection of SQL statements saved in the database that can be executed with a single CALL or EXECUTE command.
1Z0-006 Database Concepts & Terminology 4
What does DDL stand for in the context of SQL?