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DBMS Architecture Overview
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DBMS Architecture Overview

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@FreedNashville

Questions and Answers

What does the NOT NULL constraint enforce on a database column?

  • The column cannot have a null value. (correct)
  • The column must have a unique value.
  • The column must have a default value.
  • The column can contain duplicate values.

    • Which key is used to uniquely identify every row in a table?

  • Surrogate key
  • Primary key (correct)
  • Foreign key
  • Candidate key

    • What is the purpose of the UNIQUE constraint in a database?

  • To automatically increment the value in a column.
  • To allow duplicate values in a column.
  • To ensure a column contains only unique values. (correct)
  • To set a default value for a column.

    • What occurs when an auto-increment is applied to a column?

    <p>The column automatically generates a unique value starting from one.</p> Signup and view all the answers

    Which of the following represents a column that allows duplicates but does not allow null values?

    <p>NOT NULL</p> Signup and view all the answers

    In database terminology, what does the term 'Tuple' refer to?

    <p>A row in a table.</p> Signup and view all the answers

    What distinguishes a Foreign key from other types of keys?

    <p>It refers to a primary key in another table.</p> Signup and view all the answers

    Which type of key can consist of multiple columns to identify rows uniquely in a table?

    <p>Composite key</p> Signup and view all the answers

    What does the DEFAULT constraint define for a database column?

    <p>A default value will be assigned if no value is provided.</p> Signup and view all the answers

    Which type of key is used to identify alternative candidate keys in a table?

    <p>Alternate key</p> Signup and view all the answers

    Which SQL command is used to permanently remove a table from a database?

    <p>DROP</p> Signup and view all the answers

    What does the SQL command INSERT do?

    <p>Add new data to the database</p> Signup and view all the answers

    Which of the following commands is NOT a Data Control Language (DCL) command?

    <p>ROLLBACK</p> Signup and view all the answers

    Which command allows you to undo changes made in the database?

    <p>ROLLBACK</p> Signup and view all the answers

    If you want to add a new column to an existing table, which command would you use?

    <p>ALTER</p> Signup and view all the answers

    What is the purpose of the TRUNCATE command in SQL?

    <p>Permanently delete all rows in a table</p> Signup and view all the answers

    What type of SQL command is COMMIT considered to be?

    <p>Transaction Control Language (TCL)</p> Signup and view all the answers

    Which SQL command is used to change existing data in a database table?

    <p>UPDATE</p> Signup and view all the answers

    Which SQL command would you use to give users access privileges to a database?

    <p>GRANT</p> Signup and view all the answers

    When using the SAVEPOINT command, what is its primary function?

    <p>To create a point to which you can later roll back transactions</p> Signup and view all the answers

    What is the updated marks for the student with stud_id S001?

    <p>95</p> Signup and view all the answers

    What changes were made to the student named Thilan?

    <p>The subject was updated to English and marks to 50.</p> Signup and view all the answers

    What is the new full name for the student currently known as Isuru Kalhara?

    <p>Pasan Nimesh</p> Signup and view all the answers

    Which student record was removed from the student_details table?

    <p>S010</p> Signup and view all the answers

    Which details are sought for the student with stud_id S002?

    <p>f_name, l_name, nic, age</p> Signup and view all the answers

    What primary change is being queried in the student_details table?

    <p>f_name, l_name, and nic</p> Signup and view all the answers

    What was the original subject for the student identified as S005?

    <p>ICT</p> Signup and view all the answers

    How many students scored above 80 marks in the marks column?

    <p>3</p> Signup and view all the answers

    Which command is used to permanently delete a database and its objects?

    <p>DROP</p> Signup and view all the answers

    What is the primary purpose of the UPDATE command in DML?

    <p>To modify existing records in a table</p> Signup and view all the answers

    Which of the following activities is NOT associated with Data Definition Language (DDL)?

    <p>Inserting data into tables</p> Signup and view all the answers

    In the context of Data Manipulation Language, what is the purpose of the SELECT command?

    <p>To retrieve information from a table</p> Signup and view all the answers

    Which command would you use to add new attributes to an existing table structure?

    <p>ALTER</p> Signup and view all the answers

    What defines a 1 tier Architecture in DBMS?

    <p>All components reside on the same machine.</p> Signup and view all the answers

    Which characteristic is NOT true of the 2 tier Architecture?

    <p>There is an intermediary between the client and the database.</p> Signup and view all the answers

    What is the primary feature of the 3 tier Architecture?

    <p>A server is always required between clients and the database.</p> Signup and view all the answers

    Which of the following is a feature of ANSI-SPARC Architecture?

    <p>It is governed by the American National Standards Institute.</p> Signup and view all the answers

    In a 1 tier DBMS Architecture, which of the following is true?

    <p>All components are hosted on a single machine.</p> Signup and view all the answers

    What is a significant drawback of 2 tier architecture?

    <p>Scalability becomes an issue.</p> Signup and view all the answers

    Which language is essential for 3 tier Architecture to function?

    <p>SQL</p> Signup and view all the answers

    How does a client interact with the database in 1 tier Architecture?

    <p>Directly with no intermediaries.</p> Signup and view all the answers

    Which is a primary benefit of 3 tier Architecture?

    <p>Improved security and flexibility.</p> Signup and view all the answers

    What does three-schema architecture refer to in ANSI-SPARC?

    <p>Three distinct layers of database management.</p> Signup and view all the answers

    Study Notes

    DBMS Architecture

    • DBMS Architecture represents the design of a Database Management System.
    • Composed of three main types: Single Tier, Two Tier, and Three Tier Architecture.

    Single Tier Architecture

    • All components (client, server, database) reside on the same machine.
    • Simplifies the system as it does not require intermediate communication.

    Two Tier Architecture

    • Client application communicates directly with the database.
    • Allows multiple clients to connect to a single database without an intermediary.

    Three Tier Architecture

    • Includes a client, a server, and a database, enabling indirect communication.
    • Clients do not communicate directly with the database but through a server.
    • Utilizes Structured Query Language (SQL) for communication.

    ANSI-SPARC Architecture

    • Refers to the Three Schema Architecture.
    • Implemented by the American National Standards Institute (ANSI) and the Standards Planning and Requirements Committee (SPARC).

    SQL Commands

    • SQL commands are instructions for communicating with a database.
    • Commands are categorized into Data Definition Language (DDL), Data Manipulation Language (DML), Data Control Language (DCL), Transaction Control Language (TCL), and Data Query Language (DQL).

    Data Definition Language (DDL)

    • Creates, alters, and removes database objects.
    • Key Commands:
      • CREATE: Used for creating tables or databases.
      • ALTER: Used to modify existing tables.
      • DROP: Permanently deletes tables or databases.
      • TRUNCATE: Removes all records from a table without deleting the structure.

    Data Manipulation Language (DML)

    • Manages data in existing databases but does not change the structure.
    • Key Commands:
      • INSERT: Adds new records to a table.
      • UPDATE: Modifies existing records.
      • DELETE: Removes records from a table.

    Data Control Language (DCL)

    • Manages user permissions.
    • Key Commands:
      • GRANT: Assigns access privileges to users.
      • REVOKE: Removes access privileges from users.

    Transaction Control Language (TCL)

    • Controls transactions within a database.
    • Key Commands:
      • COMMIT: Saves all changes made in a transaction.
      • ROLLBACK: Undoes changes made in the transaction.
      • SAVEPOINT: Sets a point within a transaction to which you can later roll back.

    Database Constraints

    • Rules that enforce limits on data in a table.
    • Examples of constraints:
      • NOT NULL: Ensures a field cannot be empty.
      • UNIQUE: Guarantees all values in a column are different.
      • DEFAULT: Sets a default value for a column if no value is provided.
      • AUTO INCREMENT: Automatically generates a unique value for new records.

    Keys in Database Management

    • Different types of keys used to uniquely identify records:
      • Super Key: A combination of attributes that can uniquely identify a tuple.
      • Candidate Key: A minimal super key.
      • Primary Key: A selected candidate key used to uniquely identify records.
      • Foreign Key: An attribute linked to the primary key of another table.

    Difference between DDL and DML

    • DDL: Focuses on database structure creation and modification.
    • DML: Responsible for managing and manipulating existing data within the tables.

    Example SQL Operations

    • Inserting new records:
      • INSERT INTO student_details (stud_id, f_name, l_name, nic, address, age, subject, marks) VALUES ('S001', 'Sandun', 'Perera', '957414152V', '50,1st lane, kottawa', 28, 'Maths', 85);
    • Updating records:
      • UPDATE student_details SET marks = '95' WHERE stud_id = 'S001';
    • Deleting records:
      • DELETE FROM student_details WHERE stud_id = 'S010';
    • Querying specific data:
      • SELECT f_name, l_name, nic, age FROM student_details WHERE stud_id = 'S002';

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    Related Documents

    dbms.pdf

    Description

    This quiz explores the different types of DBMS architecture, including single tier and multi-tier designs. Understanding these architectures is vital for effective database management system design. Test your knowledge on the various approaches to DBMS architecture.

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