Database fundamentals practice set #1(iT fundamentals)

In SQL, which statements are used to grant or deny specific rights to user accounts over objects in the database?

• Data Control Language

• Data definition Language

• Data manipulation language

• Data query language

Answer explanation

DCL commands in SQL, such as GRANT and DENY, are used to control access rights for user accounts over objects in the database. They allow specific permissions to be granted or denied to users for performing actions on tables, columns, views, and the database itself. Data Query Language (DQL) is not a widely used term in SQL. While queries are an essential part of retrieving data, the term DQL is not commonly used to represent a specific category of commands related to granting or denying access rights. Data Definition Language (DDL) commands, such as CREATE and DROP, are used to define and manage the structure of a database, including creating tables, altering table structures, and defining constraints. DDL commands do not directly deal with granting or denying access rights to user accounts. Data Manipulation Language (DML) commands are used to manipulate data within a database, such as inserting, updating, or querying records. DML commands do not directly involve granting or denying specific rights to user accounts.

How do document databases differ from traditional relational databases?

• Document database cannot establish data relationship

• Document database only store text documents

• document database store data in a semi-structured format allowing for flexibility in a data structure.

• document database are inherently slower

Answer explanation

Document databases, unlike traditional relational databases, are designed to store, retrieve, and manage document-oriented information, often in a semi-structured format like JSON. This design allows for more flexibility in data structure. Contrary to this, document databases can model relationships, albeit differently from relational databases, such as through nesting data within a single document. While the name might suggest it, document databases do not exclusively store text documents. They use a document-oriented model to manage more varied data types. Speed depends on various factors, not just the type of database. For certain types of data and queries, document databases can even be faster.

Your company's CEO has just tasked your IT team with creating a safeguarding measure that could be used to completely restore the customer database in the event of a system failure or data loss. This measure should include a comprehensive backup of all data and structures in a format that can be used to recreate the original database. What term BEST describes this safety measure?

• using a query builder and report generation tools

• the process of assigning roles and permissions

• manual scripting of SQL commands for database interaction

• Creating a data Dump

Answer explanation

A Database Dump involves creating a backup of a database, which includes all data and structure in a form such that it can be used to recreate the original database if needed. It's the hero in your disaster recovery plan! Though SQL scripting carries its own significance in database operations, it doesn't aid in recreating the database after a sudden data loss or system mishap. While managing roles and permissions is vital for database security, it doesn't serve as a safeguard for recovery in the event of data loss or system failure. Despite the usefulness of query builders and reporting tools, they can't restore the full database in case of catastrophic system failure or data breach.

Which of the following BEST describes one of the main purposes of a database?

• to provide a structured storage of data

• the design website interface

• to automate document creation

• to create animation for videos

Answer explanation

A key purpose of a database is to provide structured storage of data. This allows for efficient and organized data retrieval, modification, and storage. Databases are not usually involved in creating animations for video games. Instead, game developers use specialized software for this task. Databases are not typically used to design website interfaces. This is generally the role of UI/UX design tools and front-end programming languages. While databases can store information used in documents, they are not typically used to automate document creation. This task typically falls under document automation software.

Which of the following is designed to efficiently handle multiple concurrent users?

• Databases

• Both databases and flash files

• Flat files

• Neither databases and flash files

Answer explanation

Databases are designed to handle multiple concurrent users. They have mechanisms in place (like locking and transaction control) to handle simultaneous access and modification of data, ensuring data consistency and integrity. Flat files do not have in-built support for managing multiple concurrent users. They lack the advanced features of databases, such as record locking, which can lead to problems with data consistency and integrity when accessed by multiple users simultaneously. While both databases and flat files can be accessed by multiple users, only databases have mechanisms to handle simultaneous access and modification efficiently and safely. Databases do have robust mechanisms for dealing with multiple concurrent users, ensuring that multiple users can access and modify the data efficiently without compromising data integrity.

When designing a database, what feature allows you to impose certain limitations on the values that can be entered into each field, ensuring consistency and data integrity?

• Normalization

• constraints

• Encryption

• Indexing

Answer explanation

Constraints in databases are rules that are applied to data, both during insertion and updating, to ensure the data matches certain specifications. Constraints help maintain the quality, integrity, and accuracy of data. Indexing is a database feature that enhances search performance by creating indexes on specific columns. While indexing improves query speed, it does not impose constraints on the values entered into each field. Normalization is a technique used in database design to eliminate data redundancy and ensure data integrity. However, it does not directly relate to imposing constraints on the values entered into fields. Encryption is a security measure that transforms data into an unreadable format to protect it from unauthorized access. While encryption provides data protection, it does not restrict or enforce constraints on the values entered into fields.

Which of the following BEST describes the function of a table in a Database Management System (DBMS)?

• to speed up the query processing engine

• to record the transaction history in the database

• to store the related records, each consisting of one or more fields

• to determine the user access permission in the database

Answer explanation

A table in a DBMS is used to store related records. Each record is represented as a row in the table, and each field (or attribute) is represented as a column. While some tables might be used to record transaction history as part of a logging or audit process, this is not the primary function of tables in a DBMS. While user access permissions are an essential aspect of DBMS, they are generally managed separately and are not the primary function of a table. While well-designed table structures can potentially improve query speed by enabling efficient data retrieval, the main function of a table is to store data, not directly enhance query speed. Improving query processing speed is typically addressed through other strategies, like indexing.

In which of the following scenarios would a database manager need to use the CREATE command?

• When they want to extract specific information from a table

• when they need to add a new table in the database

• when they need to remove an un wanted table from the database

• when they want to modify the stature of an existing table

Answer explanation

Explanation

The CREATE command is used to create a new table or a whole new database. The SELECT command, not the CREATE command, is used to retrieve specific data from a database. The ALTER command, not the CREATE command, is used to modify the structure of an existing table. The DROP command, not the CREATE command, is used to remove a table or a whole database.