Database Systems — Part 1 MCQs with Explanations

The PROJECT command is like taking that big table and saying: "I only want to see these specific columns (fields) from it." It creates a BRAND NEW TABLE that only contains the columns you asked for. Let's look at the options: Option A: more fields than the original table This is INCORRECT . When you use PROJECT, you are *selecting* fields that already exist. You can choose to see *fewer* fields or *all* fields from the original table, but you can never magically create *new* fields that weren't there before. So, it will never have *more* fields. Option B: more rows than the original table This is also INCORRECT . The PROJECT command focuses on which *columns* you see. It doesn't add new entries (rows) to your table. In fact, if selecting fewer columns makes some rows look exactly the same, the PROJECT command usually removes those duplicate rows. This means the new table might even have *fewer* rows, but never *more*. Option C: both (a) and (b) Since both (a) and (b) are incorrect, this option is also INCORRECT . Option D: all the fields of master table This is partially true in a specific scenario, but it's NOT generally what PROJECT does or its defining characteristic. You *can* use PROJECT to select *all* fields from the original table, but its main purpose is to let you pick a *subset* of fields. If you always wanted all fields, you wouldn't need a special command to "project" them; you'd just use a simple selection of everything. The command's flexibility means it *can* select all, but it doesn't *always* do so, and it doesn't *have* to. It's about *choosing* fields. Option E: None of the above This is the CORRECT answer. The PROJECT command creates a new table that has: * Fewer or the same number of fields as the original table (never more). * Fewer or the same number of rows as the original table (never more, due to duplicate removal). So, none of the options A, B, or D accurately describe the general outcome of the PROJECT command.

In a database environment, the components typically include: Users: Individuals who interact with the database to perform operations like querying and updating data. Database: The structured collection of data that is managed and organized for efficient retrieval and manipulation. Database Administrator: The person responsible for managing and maintaining the database system, ensuring its performance, security, and availability. Separate Files: This is not considered a component of a modern database environment. Databases are designed to manage data within a centralized system rather than relying on multiple separate files. Thus, Option B: separate files is the correct answer as it does not fit into the standard components of a database environment.

A logical schema is a representation of the structure of a database in terms of how data is organized and related. It focuses on the design and organization of data elements and their relationships, abstracted from the physical storage. Logical Schema Definition: The logical schema defines how data is organized into tables , their attributes, and the relationships among them. It is concerned with the design and structure of the database as seen by users and applications, without regard to how the data is physically stored. Option A: Entire Database This describes the physical schema or the entire database, not the logical schema. Option C: Describes How Data is Actually Stored This refers to the physical schema , which deals with the actual storage of data on disk. Option D: All of the Above Since options A and C describe different aspects (physical schema) and are not part of the logical schema, this option is incorrect. Option E: None of the Above Since option B correctly describes the logical schema, this option is not applicable. Therefore, the correct answer is Option B: is a standard way of organizing information into accessible parts .

print files on paper is the correct answer to “A report generator is used to”. This question is standard in competitive examination syllabi for Database Systems.

chain is the correct answer to “Which of the following is not a logical data-base structure”. This question is standard in competitive examination syllabi for Database Systems.

All of the above is the correct answer to “Which of the following is a database administrator's function”. This question is standard in competitive examination syllabi for Database Systems.

Look-up is the correct answer to “Primitive operations common to all record management systems include”. This question is standard in competitive examination syllabi for Database Systems.

File structure is the correct answer to “Each of data files has a _____ that describe the way the data is stored in the file.”. This question is standard in competitive examination syllabi for Database Systems.

Update is the correct answer to “After you _____ a record, many data management the environments require you to issue a command to save the changes you made.”. This question is standard in competitive examination syllabi for Database Systems.

Query language is the correct answer to “What is the language used by most of the DBMSs for helping their users to access data”. This question is standard in competitive examination syllabi for Database Systems.

width is the correct answer to “Data item characteristics that are important in data management include”. This question is standard in competitive examination syllabi for Database Systems.

COMMIT is the correct answer to “In SQL, which command is used to make permanent changes made by statements issue since the beginning of a transaction”. This question is standard in competitive examination syllabi for Database Systems.

Updating is the correct answer to “Periodically adding, changing and deleting file records is called file”. This question is standard in competitive examination syllabi for Database Systems.

require more disk space than index/report generators is the correct answer to “Sort/report generators”. This question is standard in competitive examination syllabi for Database Systems.

All of the above is the correct answer to “The data dictionary tells the DBMS”. This question is standard in competitive examination syllabi for Database Systems.

ALTER TRIGGER is the correct answer to “In SQL, which command(s) is(are) used to enable/disable a database trigger”. This question is standard in competitive examination syllabi for Database Systems.

correct spelling changes before they are recorded is the correct answer to “If the record management system allows you to edit values before they are recorded on disk, you can”. This question is standard in competitive examination syllabi for Database Systems.

record is the correct answer to “The relational model uses some unfamiliar terminology. A tuple is equivalent to a:”. This question is standard in competitive examination syllabi for Database Systems.

Data field is the correct answer to “The files stored on a secondary stage device are composed of a hierarchy of data. What does a record in a file contain”. This question is standard in competitive examination syllabi for Database Systems.

DROP INDEX is the correct answer to “Which command is used to remove an index from the database in SQL”. This question is standard in competitive examination syllabi for Database Systems.

only one owner but many owner occurrences is the correct answer to “An-owner-member set in the CODASYL specifications may have”. This question is standard in competitive examination syllabi for Database Systems.

Multimedia is the correct answer to “What is the name given to the database management system which is able to handle full text data, image data, audio and video”. This question is standard in competitive examination syllabi for Database Systems.

Hierarchical schema is the correct answer to “A top-to-bottom relationship among the items in a database is established by a”. This question is standard in competitive examination syllabi for Database Systems.

both (a) and (b) is the correct answer to “A database management system”. This question is standard in competitive examination syllabi for Database Systems.

high speed, large-capacity disk is the correct answer to “Which of the following hardware components is the most important to the operation of a database management system”. This question is standard in competitive examination syllabi for Database Systems.

All of the above is the correct answer to “To have a file hold a list, it is necessary to”. This question is standard in competitive examination syllabi for Database Systems.

All of the above is the correct answer to “Sophisticated report generators can”. This question is standard in competitive examination syllabi for Database Systems.

Hierarchical database is the correct answer to “In a _____ a parent record type can be linked to one or more "child" record types, but a child record type can have only one parent.”. This question is standard in competitive examination syllabi for Database Systems.

data dictionary and transaction log is the correct answer to “Which two files are used during operation of the DBMS”. This question is standard in competitive examination syllabi for Database Systems.

load the software into your micro¬computer is the correct answer to “When using a database management system, the first thing that you must do is to”. This question is standard in competitive examination syllabi for Database Systems.

permits many-to-many relation¬ships is the correct answer to “A network schema”. This question is standard in competitive examination syllabi for Database Systems.

Reflex is the correct answer to “Which of the following is not a relational database”. This question is standard in competitive examination syllabi for Database Systems.

DROP TABLE is the correct answer to “Which command is used to remove a table from the database in SQL”. This question is standard in competitive examination syllabi for Database Systems.

Master file is the correct answer to “A large computer information system maintains many different computer files. Which amongst them is called a perpetual file”. This question is standard in competitive examination syllabi for Database Systems.

is generally stored on disk in an ASCII text format is the correct answer to “A file produced by a spreadsheet”. This question is standard in competitive examination syllabi for Database Systems.

both (a) and (b) is the correct answer to “A form defines”. This question is standard in competitive examination syllabi for Database Systems.

It allows a many-to-many relationship is the correct answer to “Which of the following is true of a network structure”. This question is standard in competitive examination syllabi for Database Systems.

grant system privileges, roles, and object privileges to uses and roles is the correct answer to “In SQL, GRANT command is used to”. This question is standard in competitive examination syllabi for Database Systems.

database is the correct answer to “The highest level in the hierarchy of data organization is called”. This question is standard in competitive examination syllabi for Database Systems.

tree is the correct answer to “The logical data structure with a one-to-many relationship is a :”. This question is standard in competitive examination syllabi for Database Systems.