Introduction to SQL Server

SQL Server

• Introduction 
• What is SQL Server
• Usage of SQL Server
• SQL Server Editions
• SQL Server Client Server Architecture
• SQL Server Architecture (Explained)
• SQL Server Tools
• SQL Server Services
• Database Management System
• DBMS -Services
•  Data Definition
• Data Manipulation
• Data Integrity
• Entity Relational Model (E-R Model)
• Entity
• Attributes

• Relationship among Data
• One to One
• One to Many
• Many to Many
• Database Models Types
• 
  

Introduction    

SQL Server is a Client/Server Relational Database Management System (RDBMS) that uses Transact-SQL to send request between a client and SQL Server.

• SQL Server is designed to be a client/server system. Client/server systems are constructed so that the database can reside on a central computer, known as a Server, and be shared among several users.
• When users want to access the data in SQL Server, they run an application on their local computer, known as a client, that connects over a network to the server running SQL Server
• SQL Server can work with thousands of client application simultaneously. 
•  The server has features to prevent the logical problems that occur if a user tries to read or modify data currently used by others.
• While SQL Server is designed to work as a sever in a Client/Server network, it is also capable of working as a stand-alone database directly on the client. 
• The scalability and easy-to-use features of SQL Server allow it to work efficiently on a client without consuming too many resources.

What is SQL Server?

• The relational database management system (RDBMS) is a Microsoft software product mainly used to store and retrieve data for the same or other applications. We can run these applications on the same computer or a different one.
• Microsoft developed and marketed the SQL Server relational database management system (RDBMS) to primarily compete with the MySQL and Oracle databases. It is also called MS SQL Server, which is an ORDBMS, platform-dependent, and can work on GUI and command-based software.
•  The key interface tool for SQL Server is SQL Server Management Studio (SSMS), which operates in both 32-bit and 64-bit environments.

Usage of SQL Server

The following are the key usage of MS SQL Server:

• Its main purpose is to build and maintain databases.
• It is used to analyze the data using SQL Server Analysis Services (SSAS).
• It is used to generate reports using SQL Server Reporting Services (SSRS).
• It is used to perform ETL operations using SQL Server Integration Services (SSIS).

SQL Server Editions

SQL Server comprises five editions with different bundled services and tools and pricing options to meet the user needs. 

Microsoft provides two editions of SQL Server free of charge, which are given below:

1. SQL Server Developer: 
• This edition was released mainly for use in the non-production environment, i.e., database development and testing. It allows to build, test, and demo purpose.
2. SQL Server Express: 
• It is used for small-scale applications and databases with disc storage capacities of up to 10 GB.

For commercial purposes, the following editions are used:

1. SQL Server Enterprise: 
• It is used in high-end, larger, and more critical businesses. All SQL Server features, such as high-end security, advanced analytics, and machine learning, are included in this version.
2. SQL Server Standard: 
• This edition is suitable for data marts and mid-tier applications that included basic reporting and analytics. It supports partial enterprise edition's feature, as well as server limitations on the number of processor cores and memory that we can configure.
3. SQL Server WEB: 
• This edition is suitable for Web hosters who want a low overall ownership cost. It has features of scalability, manageability capabilities, and affordability for small to large-scale web properties.

SQL Server as Client-Server Architecture

• SQL Server is based on a Client-Server Architecture and is intended for end-users known as clients who send requests to the MS SQL Server installed on a particular computer. 
• The server will give the desired output as soon as the processing input data is requested. 
• This server is available as a separate program and responsible for handling all the database instructions, statements, or commands. 
• The SQL Server Database Engine, which controls data storage, processing, and security, is thus the core component of MS SQL Server.

SQL Server Architecture (Explained)

Link to SQL Server Architecture Detailed Desc..

• MS SQL Server is a client-server architecture. MS SQL Server process starts with the client application sending a request. 
• The SQL Server accepts, processes and replies to the request with processed data. Let’s discuss in detail the entire architecture shown below:
• As the below Diagram depicts there are three major components in SQL Server Architecture:
• Protocol Layer
• Relational Engine
• Storage Engine

Let’s discuss in detail about all the three above major modules. In this tutorial, you will learn.

• Protocol Layer – SNI
• Shared Memory
• TCP/IP
• Named Pipes
• What is TDS?
• Relational Engine
• CMD Parser
• Optimizer
• Query Executor
• Storage Engine
• File types
• Access Method
• Buffer Manager
• Plan Cache
• Data Parsing: Buffer cache & Data Storage
• Transaction Manager

SQl Server Tools: 

• SQLCMD: 
• SQLCMD is a command line application that comes with Microsoft SQL Server, and exposes the management features of SQL Server. It allows SQL queries to be written and executed from the command prompt. It can also act as a scripting language to create and run a set of SQL statements as a script. Such scripts are stored as a .sql file, and are used either for management of databases or to create the database schema during the deployment of a database. 
• Visual Studio: 
• Microsoft Visual Studio includes native support for data programming with Microsoft SQL Server. It can be used to write and debug code to be executed by SQL CLR.
• SQL Server Management Studio: 
• SQL Server Management Studio is a GUI tool included with SQL Server 2005 and later for configuring, managing, and administering all components within Microsoft SQL Server. The tool includes both script editors and graphical tools that work with objects and features of the server. 

SQL Server Services:

 SQL Server also includes an assortment of add-on services. While these are not essential for the operation of the database system, they provide value added services on top of the core database management system. These services either run as a part of some SQL Server component or out-of-process as Windows Service and presents their own API to control and interact with them.

• Analysis Services:
•  SQL Server Analysis Services adds OLAP and data mining capabilities for SQL Server databases. The OLAP engine supports MOLAP, ROLAP and HOLAP storage modes for data. Analysis Services supports the XML for Analysis standard as the underlying communication protocol. The cube data can be accessed using MDX queries. Data mining specific functionality is exposed via the DMX query language.
• Reporting Services: 
• SQL Server Reporting Services is a report generation environment for data gathered from SQL Server databases. It is administered via a web interface. Reporting services features a web services interface to support the development of custom reporting applications. Reports are created as RDL files. Reports can be designed using recent versions of Microsoft Visual Studio (Visual Studio.NET 2003, 2005, and 2008) with Business Intelligence Development Studio, installed or with the included Report Builder. Once created, RDL files can be rendered in a variety of formats including Excel, PDF, CSV, XML, TIFF (and other image formats), and HTML Web Archive
• Integration Services: 
• SQL Server Integration Services is used to integrate data from different data sources. It is used for the ETL capabilities for SQL Server for data warehousing needs. Integration Services includes GUI tools to build data extraction workflows integration various functionality such as extracting data from various sources, querying data, transforming data including aggregating, duplication and merging data, and then loading the transformed data onto other sources,

Database Management System

A brief overview of the relational database model is provided as the SQL Server database is based on this model.

• A Database Management System is a set of computer programs that controls the creation, maintenance, and the use of a database.
•  It allows organizations to place control of database development in the hands of database administrators (DBAs) and other specialists.
• In large systems, a DBMS allows users and other software to store and retrieve data in a structured way. 
• Instead of having to write computer programs to extract information, user can ask simple questions in a query language.
•  It helps to specify the logical organization for a database and access and use the information within a database. 
• It provides facilities for controlling data access, enforcing data integrity, managing concurrency, and restoring the database from backups. A DBMS also provides the ability to logically present database information to users.
•  DBMS is a system software package that helps the use of integrated collection of data records and files known as databases. 
• It allows different user application programs to easily access the same database.

Database Management systems offers the following services.

• Data Definition: 
• It is a method of data storage. 
• Data Maintenance: 
• It checks whether each record has fields containing all information about one particular item. For example, in an employee table, all information about the employee like name, address, designation, salary, dept-name. 
• Data Manipulation: 
• This method helps in viewing and manipulating data. 
• Data Integrity: 
• This ensures accuracy of data.

Entity-Relational Model (E-R Model):

Database design representation will be done using E-R model. 

• Entity: 

• An entity is a any object, place, person, concept or activity about which an enterprise records data. (Name, Price,.etc)

• Attributes: 

• An attribute is the characteristic property of an existing entity. Attribute type is the property of entity type, and attribute instance is the property of entity instance. An ellipse always represents the attribute.

Relationship among data: 

• A relationship is defined as “an association among entities”. 
• A relationship type is an association of entity types. While a relationship instance is an association of entity instances. 
• The three different types of relationships recognized among various data stored in the database are: 
• One-to-one 
• One-to-Many (or Many-to-One) 
• Many-to-Many 

• One-to-One: 
• Consider for example a set of students in a class. Each student can have only one Roll number. Similarly, each role number can be associated with on student. This is the case of a one-to-one relationship.
• Many-to-One: 
• One student can register for only one particular course at a time, whereas a number of students could register for the same course.
•  Many-to-Many: 
• A vendor can sell a number of items and many vendors can sell a particular item.

 

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Database Model Types

The three general database types based on the model are:

• Relational database
• Non-relational database (NoSQL)
• Object-oriented database

The difference between the models is the way the information looks inside the database. Consequently, each model type has a different management system and data relationships.

Relational Database:

The relational database model is the most extensively used as well as the oldest database type. The three critical components of a relational database are:

• Tables. An entity type with relations.
• Rows. Records or instances of an entity type.
• Columns. Value attributes of instances.

A relational database provides a set of data rows in response to a query. A query language, most commonly the Structured Query Language or SQL, helps create these data views.

Relational Database Features

The main features of a relational database are:

• ACID compliant. The database retrains integrity while performing transactions.
• Range of data types. Provides the capability to store any data as well as carry out complex queries.
• Collaborative. Multiple users are able to access the database and work on the same project.
• Secure. Access is limited or restricted through user permissions.
• Stable. Relational databases are well-understood and documented.

What are Relational Databases Used For?

Relational databases are the most implemented database type. There are many use cases, some of which include:

• Online transaction systems. The database supports many users as well as frequent queries needed in online transactions.
• IoT. Relational databases are lightweight and have the processing power needed for edge computing.
• Data warehouses. The critical component of the data warehouse architecture is storage. Relational databases are easily integrated and optimized for massive queries from multiple sources.

Most Popular Relational Databases

The topmost popular relational databases are:

1. Oracle
2. MySQL
3. Microsoft SQL Server
4. PostgreSQL
5. Microsoft Azure SQL Database etc...

Non-relational Database (NoSQL Database)

A non-relational database, or NoSQL ("Not Only SQL"), is a type of database that models and stores data differently from relational databases. Instead of tables, non-relational databases model relationships between data in an alternative way.

The 4 NoSQL database types are:

• Document
• Key-value
• Column based.
• Graph

Non-relational Database Features

The main features of non-relational databases are:

• Flexible. Handling structured, semi-structured, and unstructured data is a breeze with non-relational database types.
• Scalable and responsive. Massive data storage scales well with on-demand servers and provides quick query responses.
• Zero downtime. High availability for minimal downtime due to near real-time data replication.
• Cloud compatible. The scalability of a cloud computing architecture incorporates perfectly with non-relational databases.
• Multiple data structures. Different information types, as well as multi-model database formats, are available.

what are Non-relational Databases Used For?

Non-relational databases perform best with variable data structures and massive amounts of data. Some use cases include:

• Real-time systems. A non-relational database combines the operational and analytical database systems into one. Whether feeding operational data into Hadoop or serving analytics results from Hadoop, non-relational databases provide the agile real-time experience.
• Personalized experience. Elastic scaling accommodates the massive amounts of data needed for any customized experience.
• Fraud detection. High performance is vital in fraud detection. Non-relational databases are responsive and reliably meet the low latency requirements of financial systems.

Most Popular Non-Relational Databases

The ten most popular non-relational databases are:

1. MongoDB

2. Redis

3. Cassandra

4. HBase

5. Neo4j

Object Database

An object database similarly represents data to objects in object-oriented programming. The critical components of an object-oriented database are:

• Objects. The basic building blocks for storing information.
• Classes. The schema or blueprint for an object.
• Methods. Structured behaviors of a class.
• Pointers. Access elements of a database and establish relations between objects.

Object databases combine object-oriented programming concepts with database capabilities.

Object Database Features

The main features of object databases are:

• ACID transactions. All transactions are complete without conflicting changes due to ACID compliance.
• Transparent persistency. Object databases integrate seamlessly with object-oriented programming languages.
• Complex and custom data types. User-defined classes allow for custom as well as complex data types to exist.
• Accessible. Data is easy to save and retrieve.
• Easier modeling. Real-world problems and information are more closely related to objects, which makes complex problems easier to model.

What Are Object Databases Used For?

Object databases perform best with complex data types, where one entity includes a massive amount of information. Some everyday use cases for this database model type are:

• High-performance applications. Applications where fast data retrieval is vital to benefit from object databases since data is stored and retrieved as-is.
• Scientific purposes. Scientific data, as well as calculations, are complex. Storing complex information and quick retrieval find use in all kinds of scientific disciplines.
• Complex data structures. Due to permanent persistence with objects, database storage and expansion of complex data is accessible, eliminating the need to rework the database model.

Most Popular Object Databases

Currently, the top ten most popular object databases are:

1. DB4o

2. ObjectStore

3. Matisse

4. Gemstone/S