Learning Database Fundamentals

Learning Database Fundamentals

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What is DBMS ?
What is SQL and NoSQL?
What is Database, Table, Rows and Columns ?

Ans:1 DBMS:-
Data refers to any set of information that is collected, stored, and processed for various purposes. It can include facts, statistics, measurements, observations, or any other type of information that can be recorded and analyzed. Data can take various forms, such as numbers, text, images, audio, video, and more.The effective collection, storage, processing, and analysis of data have become increasingly important in today’s digital age, driving innovation and advancements across various industries.
Structured, semi-structured, and unstructured data are terms used to describe different types of data based on their organization, format, and characteristics:

  1. Structured Data:
    Structured data refers to well-organized and highly formatted data that fits neatly into predefined schemas. It is typically stored in rows and columns, similar to a table in a relational database. Structured data is easy to query, analyze, and manipulate because of its consistent format.

    Examples of structured data:

    • Tabular data in relational databases.
    • Spreadsheet data in Excel.
    • Sensor readings organized in a consistent format.
  2. Semi-Structured Data:
    Semi-structured data has some structure but does not adhere to a strict, predefined schema like structured data. While it might not fit neatly into tables, it retains a level of organization through the use of tags, keys, or attributes. Semi-structured data can be more flexible and accommodating to changes in data format.

    Examples of semi-structured data:

    • JSON (JavaScript Object Notation) documents.
    • XML (eXtensible Markup Language) files.
    • NoSQL databases that allow for varying data structures within the same collection.
  3. Unstructured Data:
    Unstructured data lacks a specific structure or format. It doesn’t conform to rows and columns or any predefined schema. Unstructured data is often more complex and may require advanced techniques for analysis. It can include text, images, audio, video, and more.

    Examples of unstructured data:

    • Textual content like emails, articles, or social media posts.
    • Images and videos.
    • Audio recordings.
    • Free-form notes or documents.

The distinction between these types of data is important because different data types require different storage, processing, and analysis methods. For instance, structured data is well-suited for traditional relational databases, while semi-structured and unstructured data often find use in NoSQL databases, content management systems, and specialized tools for text or multimedia analysis.

A database is a structured collection of data that is organized, stored, and managed in a way that allows for efficient retrieval, manipulation, and querying of information. It serves as a central repository for storing various types of data, such as text, numbers, images, videos, and more. Databases are used to manage and organize data in a structured manner, enabling users and applications to interact with and retrieve information in a systematic and efficient manner.

A Database Management System (DBMS) is a software system designed to manage, organize, and facilitate the storage, retrieval, modification, and administration of data in a database. In other words, a DBMS is a tool that provides an interface for users and applications to interact with databases while abstracting the underlying complexities of data storage and management. DBMS plays a crucial role in modern information systems and applications, serving as a foundation for data storage, retrieval, and management in various domains, such as business, finance, healthcare, e-commerce, and more.

Ans2:- SQL and NoSQL:-
SQL stands for Structured Query Language, and it is a domain-specific language used for managing and manipulating relational databases. SQL provides a standardized way to interact with databases, allowing users and applications to perform various operations such as querying data, inserting, updating, and deleting records, defining and modifying database structures, and more.
SQL is used with various types of database management systems, including relational databases (RDBMS), which organize data into structured tables with rows and columns. Examples of popular relational database systems that use SQL as their query language include:

  • MySQL
  • PostgreSQL
  • Microsoft SQL Server
  • Oracle Database
  • SQLite

SQL is an essential skill for database administrators, data analysts, software developers, and anyone working with data-driven applications. It provides a standardized and powerful way to interact with databases, retrieve meaningful insights, and perform various data-related tasks.

NoSQL (short for “Not Only SQL”) is a term used to describe a category of database management systems that depart from the traditional relational database model. NoSQL databases are designed to handle large volumes of unstructured or semi-structured data, provide high performance, and offer flexible and scalable data storage solutions. They are particularly suited for use cases where data requirements are rapidly evolving, and the need for horizontal scalability is paramount.
Types of NoSQL databases include:

  • Document-Based: Store data in flexible, semi-structured documents (e.g., JSON or XML). Example: MongoDB.
  • Key-Value Stores: Store data as key-value pairs. Example: Redis, Amazon DynamoDB.
  • Column-Family Stores: Store data in column families, which are groups of related data. Example: Apache Cassandra.
  • Graph Databases: Store data as nodes and edges in a graph structure. Example: Neo4j.

NoSQL databases are widely used in various applications and industries, including real-time analytics, social media, content management systems, e-commerce, IoT (Internet of Things), and more. However, it’s important to note that while NoSQL databases offer advantages in terms of scalability and flexibility, they may require careful consideration of data consistency and application requirements, as they may not provide the same level of transactional consistency as traditional relational databases.

Ans3:-Tables, Rows and Columns:-
In a relational database, which is a type of database management system (DBMS), data is organized into structured units called tables. Tables are composed of rows and columns, each of which serves a specific purpose in organizing and storing data.

  1. Table: A table is a fundamental component of a relational database. It is a collection of related data organized into rows and columns. Each table typically represents a specific entity or concept, such as customers, orders, products, etc.
  2. Row: A row, also known as a record or tuple, represents a single instance or entry of data within a table. Each row contains data values corresponding to the attributes or fields defined by the table’s schema. For example, in a “Customers” table, each row could represent information about an individual customer, with each column holding different pieces of data like customer ID, name, address, etc.
  3. Column: A column, also known as an attribute or field, represents a specific type of data that each row in the table contains. Columns define the structure of the data and provide a way to categorize and store information. For instance, in a “Products” table, columns could include product ID, product name, price, and quantity.

Here’s a simple example to illustrate the concept:

Consider a “Students” table:

StudentID FirstName LastName Age Grade
1 John Smith 18 A
2 Jane Doe 17 B
3 Alex Johnson 19 A
  • “StudentID,” “FirstName,” “LastName,” “Age,” and “Grade” are columns, each representing a specific attribute of a student.
  • Each row (record) corresponds to a single student and holds values for each attribute. For example, the first row represents a student with StudentID 1, named John Smith, aged 18, and with a grade of A.

Relational databases use this tabular structure with rows and columns to organize, store, and manage data efficiently. The relationships between tables are established through keys (such as primary keys and foreign keys), allowing for the representation of complex data models and enabling powerful querying and analysis capabilities.

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  1. What is DBMS?

Database management systems are software systems used to manage and manipulate data in a database. As most application performance issues originate in the database, knowing how to monitor and optimize your database is essential to your operations.

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What is SQL and NoSQL?

SQL- Structured query language (SQL) is a programming language for storing and processing information in a relational database . A relational database stores information in tabular form, with rows and columns representing different data attributes and the various relationships between the data values.

NOSQL-A NoSQL database provides a mechanism for storage and retrieval of data that is modeled in means other than the tabular relations used in relational databases.

3.what is database,table,column rows.

Database -A database is collection of data.
Table- collect the data in row and column format.

Rows-Actual record
Column - Attribute information.

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Q1: What is DBMS?
-> A database management system (DBMS) is system software for creating and managing databases. 
-> A DBMS makes it possible for end users to create, protect, read, update and delete data in a database.
-> It essentially serves as an interface between databases and users or application programs, ensuring that data is consistently organized and remains easily accessible.

*  What does a DBMS do?
-> DBMS manages the data; the database engine allows data to be accessed (read), locked and modified; and the database schema defines the database's logical structure.
-> These three foundational elements help provide concurrency, security, data integrity and uniform data administration procedures.
-> The DBMS supports many typical database administration tasks, including change management, performance monitoring and tuning, security, and backup and recovery.
-> Most database management systems are also responsible for automated rollbacks and restarts as well as logging and auditing of activity in databases and the applications that access them.
-> The DBMS provides a centralized view of data that can be accessed by multiple users from multiple locations in a controlled manner.
-> A DBMS can limit what data end users see and how they view the data, providing many views of a single database schema.
-> End users and software programs are free from having to understand where the data is physically located or on what type of storage medium it resides because the DBMS handles all requests.
-> The DBMS can offer both logical and physical data independence to protect users and applications from having to know where data is stored or from being concerned about changes to the physical structure of data.
-> So long as programs use the application programming interface (API) for the database that the DBMS provides, developers won't have to modify programs just because changes have been made to the database.
-> Popular database models and management systems include RDBMS, NoSQL DBMS, NewSQL DBMS, in-memory DBMS, columnar DBMS, multi-model DBMS and cloud DBMS.

Components of  DBMS:-
-> Storage engine
-> Metadata catolog
-> Database Access Language
-> Optimization engine
-> Query Processor
-> Lock Manager
-> Log Manager
-> Data Utilities

Q2: What is SQL and NoSQL?
* SQL ( Structured Query Language): [Only in TABLE FORMAT]
   -> It is used to manage data stored in relational databases like MySQL, MS Access, SQL Server, Oracle, Sybase, Informix, Postgres etc.
   -> SQL is a database computer language designed for the retrieval and management of data in a relational databases
  -> SQL was developed in the 1970s by IBM Computer Scientists/Researchers.
  -> It is used to operate on the data stored in a database. SQL depends on relational algebra and tuple relational calculus.
  -> SQL is not a database management system, but it is a query language which is used to store and retrieve the data from a database or SQL is a language that communicates with databases.
  -> SQL makes it easy to manipulate this data using simple DML (Data Manipulation Language) Statements.
  -> Eg:-
             SELECT * FROM CUSTOMERS WHERE country = 'USA';

                           *  -> retrieve every columns from CUSTOMERS table
               WHERE -> used to filter records & to extract only those records that fulfill a specified condition.
   country = 'USA' -> This is the condition for WHERE clause says only fetch records (row) with country attribute information (column) as USA and show us.

* NoSQL ( Not only Structured Query Language): [Except TABLE FORMAT]
  -> NoSQL databases are purpose built for specific data models and have flexible schemas for building modern applications.
  -> NoSQL databases are widely recognized for their ease of development, functionality, and performance at scale.
  -> It is a Non-Relational Database which just stores data differently compared to an RDBMS.
  -> The decision to use a relational database versus a non-relational database is largely contextual, and it varies depending on the use case.
  -> We know that MongoDB & much more are NoSQL Database, so it is very necessary to know about NoSQL Database to understand MongoDB throughly.
  -> It is generally used to store big data and real-time web applications.
  -> It provides a mechanism for storage and retrieval of data other than tabular relations model used in relational databases.
  -> In a NoSQL database, a book record is usually stored as a JSON document. 
  -> In this model, data is optimized for intuitive development and horizontal scalability.
  -> This databases use a variety of data models which is optimized specifically for applications that require large data volume, low latency, and flexible data models, which are achieved by relaxing some of the data consistency restrictions of other databases.
  -> Some examples of NoSQL database system with their category are:
         -      MongoDB, CouchDB, Cloudant (Document-based)
         -      Memcached, Redis, Coherence (key-value store)
         -      HBase, Big Table, Accumulo (Tabular)
  -> Advantages of NoSQL
        -      It supports query language.
        -      It provides fast performance.
        -      It provides horizontal scalability.
        -      High Scalability
                        NoSQL can handle an extensive amount of data because of scalability. If the data grows, NoSQL database scale it to handle that data in an efficient manner.
       -      High Availability
                       NoSQL supports auto replication. Auto replication makes it highly available because, in case of any failure, data replicates itself to the previous consistent state.

 -> Disadvantage of NoSQL
      -      Open source
                      NoSQL is an open-source database, so there is no reliable standard for NoSQL yet.
      -      Management challenge
                      Data management in NoSQL is much more complicated than relational databases. It is very challenging to install and even more hectic to manage daily.
     -       GUI is not available
                      GUI tools for NoSQL database are not easily available in the market.
     -       Backup
                      Backup is a great weak point for NoSQL databases. Some databases, like MongoDB, have no powerful approaches for data backup.

Q3: What is Database, Table, Row and Columns?
      * Database:
            -> A database is an organized collection of data, so that it can be easily accessed and managed.
            -> The main purpose of the database is to operate a large amount of information by storing, retrieving, and managing data.
            -> There are many dynamic websites on the World Wide Web nowadays which are handled through databases. For example, a model that checks the availability of rooms in a hotel. It is an example of a dynamic website that uses a database.
            -> There are many databases available like MySQL, Sybase, Oracle, MongoDB, Informix, PostgreSQL, SQL Server, etc.
            -> Modern databases are managed by the database management system (DBMS).
            -> A cylindrical structure is used to display the image of a database.
            -> Databases can be divided in 3 types:
                   (1) RDBMS (Relational Database Management System)
                   (2) OLAP (Online Analytical Processing)
                   (3) NoSQL (recently developed database)
     * Row
        => A row is defined as a horizontal arrangement of things. 
        => They spread from left to right. It is said to be the group of cells that are arranged horizontally to provide consistency. 
        => In a spreadsheet, rows are represented by the numbers written on the left-hand side. 
        => The total of the row values is shown at the extreme right. 
        => A row is an order where figures or objects are placed in a straight line. And arrangement of rows placed horizontally form left to right.
        => In the DBMS, rows are called records that contain fields. 
        => Each row has a unique number that represents it. 
        => In Microsoft excel, there are 1,048,576 numbers of rows. 
        => Examples of a row include the seats of a classroom in a school; seats of a movie theatre are allotted as 'row number 2 seat number 101', etc.
        => The arrangement of data in the form of rows makes the data convenient, prominent, and understandable for the user. 
     * Column
        => The column is defined as a vertical arrangement of things. 
        => It is said to be the group of cells that are aligned vertically. 
        => In the DBMS, columns are called fields that contain the collection of characters. 
        => They spread from top to bottom. 
        => The alphabet generally represents the headings of columns. 
        => The total of column values is shown at the extreme bottom.

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1).What is DBMS ?
Database Management Systems (DBMS) are software systems used to store, retrieve, and run queries on data . A DBMS serves as an interface between an end-user and a database, allowing users to create, read, update, and delete data in the database.

2).What is SQL and NoSQL?
What is difference between SQL and NoSQL?

SQL databases are table-based,
SQL databases are better for multi-row transactions,

while, NoSQL databases are document, key-value, graph, or wide-column stores,
NoSQL is better for unstructured data like documents or JSON.

  1. What is Database, Table, Rows and Columns ?

A database is an organized collection of structured information, or data, typically stored electronically in a computer system. A database is usually controlled by a database management system (DBMS).

=> Table, Rows, Columns

Tables are database objects that contain all the data in a database. In tables, data is logically organized in a row-and-column format similar to a spreadsheet. Each row represents a unique record, and each column represents a field(attributes) in the record.

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