IM REVIEWER 2.pdf

# Introduction to Database Management ## Data and Information - Data is a collection of raw, unorganized facts and details such as text, observations, figures, symbols, and descriptions. Data does not carry any specific purpose and has no significance by itself. - Data is measured in terms of bit...

# Introduction to Database Management ## Data and Information - Data is a collection of raw, unorganized facts and details such as text, observations, figures, symbols, and descriptions. Data does not carry any specific purpose and has no significance by itself. - Data is measured in terms of bits and bytes. ### Types of Data - **Quantitative:** Refers to numerical information such as weight, height, etc. - **Qualitative:** Refers to non-numeric information such as opinions, perceptions, etc. ### Examples of Data - **Raw numbers:** Sales figures that detail company revenue, population counts, or performance metrics. - **Text:** Written content found in books, articles, emails, or social media posts. - **Images:** Photographs, screenshots, or scanned historical documents. - **Audio and video recordings:** Everything from recorded speeches and public events to surveillance footage and home videos. ## Information - Information is processed, organized, and structured data. - It provides context for data and enables decision making. - For example, a single customer's sale at a restaurant is data, but it becomes information when the business can identify the most popular or least popular dish. ### Examples of Information - **Reports:** A business financial report pulls together various data like sales, expenses, and profits to paint a clear picture of a company's financial health. - **Summaries:** Distill a comprehensive report into the key points, making a mound of data easy to understand.. - **Visualizations:** Charts and graphs plot out data to show trends and patterns. ## Differences Between Data and Information | Data | Information | | :------------------------------ | :--------------------------------- | | Collection of facts | Puts facts into context | | Unorganized | Organized | | Does not depend on information | Depends on data | | Not sufficient for decision-making | Sufficient for decision-making | ## What is a Database - A database is an organized collection of structured information, typically stored electronically in a computer system. ## Components of a Database | Component | Description | | :----------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Hardware | Physical, electronic devices such as computers and hard disks that offer the interface between computers and real-world systems | | Software | Programs used to manage and control the database. Includes the database software, operating system, network software used to share the data with other users, and applications used to access the data. | | Data | Raw facts and information that need to be organized and processed to make it more meaningful. Includes database dictionaries which centralize, document, control, and coordinate the use of data. | | Procedures | Instructions used in a database management system, from setup to day-to-day operations. | | Database Access Language | Language used to write commands to access, update, and delete data stored in a database. | ## Key Database Terms - **Fields:** Contain detailed information about events, people, objects, and transactions. - **Record:** A collection of related fields. - **Table:** A collection of related records with a unique table name. - **Database:** A collection of related tables. ## Data Manipulation - Data manipulation refers to the process of adjusting, changing, or controlling data to achieve a specific outcome. ## DML: Data Manipulation Language - A data manipulation language (DML) is a family of computer languages including commands that allow users to manipulate data in a database. - It involves inserting, retrieving, deleting, and modifying data. - DML is mostly incorporated in SQL databases. - It resembles simple English language and enhances efficient user interaction with the system. ### DML Commands - **SELECT:** Retrieves rows from a table. Syntax: `SELECT [column name(s)] from [table name] where [conditions]`. It is the most widely used DML command. - **UPDATE:** Modifies data of one or more records. Syntax: `UPDATE [table name] SET [column name = value] where [condition]`. - **INSERT:** Adds one or more records to a database table. Syntax: `INSERT INTO [table name] [column(s)] VALUES [value(s)]`. - **DELETE:** Removes one or more records from a table. Syntax: `DELETE FROM [table name] where [condition]`. ## Data Security and Integrity - **Data security** refers to the prevention of data access from unauthorized users. - The DBA or head of department can access all the data. - Some users are only allowed to retrieve data, while others are allowed to retrieve and modify it. - **Data integrity** is defined as having data in a database that is both correct and consistent. - Certain types of procedures (rules) must be in place. - The DBMS provides different ways to implement constraints such as primary, secondary, and foreign keys which improves data integrity. ## Database Types - Databases can be classified into two primary types: - **Relational:** Organizes data into tables, rows, and columns to show relationships. They use a querying language like SQL for access, creation, and modification. - **NoSQL:** Developed as an alternative to traditional SQL databases. They are especially useful for working with large or fast-moving data that may not fit neatly into a table. ### Relational Database (SQL) Types - MySQL, Oracle, PostgreSQL, Microsoft SQL Server ### NoSQL Database Types - MongoDB, Cassandra, Redis, Couchbase ### Graph Database Types - Neo4j, OrientDB, ArangoDB ### Document-Oriented Database Types - MongoDB, CouchDB ### Key-Value Store Types - Redis, Amazon DynamoDB, Riak ### Wide-Value Store Types - Apache Cassandra, Google's Bigtable, HBase