What is the Difference Between Instance and Database in SQL Server

The main difference between instance and database in SQL server is that an instance is a copy of the sqlservr.exe executable that runs as an operating system service while a database is a systematic collection of data that stores data in tables.

SQL Server is an RDBMS developed by Microsoft. It consists of both GUI and command line. Programmers can write queries using SQL and execute them on SQL Server. SQL Server provides multiple advantages. It allows creating and managing databases and provides services such as analysis services and reporting services. Instance and Database are two terms related to SQL Server.

Key Areas Covered

1. What is Instance in SQL Server
    – Definition, Functionality
2. What is Database
     – Definition, Functionality
3. What is the Relationship Between Instance and Database in SQL Server
     – Outline of the Association
4. What is the Difference Between Instance and Database in SQL Server
     – Comparison of Key Differences

Key Terms

Database, Instance, SQL Server

What is Instance in SQL Server

An instance is a copy of the sqlserver.exe executable file. In other words, it is an installation of SQL Server. If the programmer installed SQL server n times, then n number of instances will be created. A computer can run multiple instances of the Database Engine while one instance can manage multiple databases. When sending data from a Java or .NET application, it is necessary to connect first to the instance that manages that particular database.

In a SQL server, there are two types of instances; they are the default and named. There is one default instance but, multiple named instances in an SQL server instance. If a certain connection request specified only the name of the computer, then that connection is for the default instance. When the programmer gives a name to the instance when installing it, is a named instance. In this situation, a connection request should have the computer name and instance name to connect to the instance.

What is Database in SQL Server

A database is a collection of related data that stores them in tables. A row in a table is a record or a tuple. A column is an attribute. Moreover, each column stores data of a certain type of information such as id, name, age, city, etc.  SQL Server databases are stored in the file system in files. In a database, there are one or multiple object ownership groups. They are called schemas. There are many database objects within each schema such as tables, views and stored procedures.

The programmers can manage databases in SQL server using the SQL Server Management tool. It has a graphical user interface. Therefore, it is easier to create and manage databases and database objects. Furthermore, the query editor allows writing SQL commands and executing them.

Relationship Between Instance and Database in SQL Server

• A single instance manages several databases.

Difference Between Instance and Database in SQL Server

Definition

An instance is a copy of the sqlservr.exe executable that runs as an operating system service. A database is a collection of tables that stores a specific set of structured data. Thus, these definitions contain the main difference between instance and database in SQL server.

Basis

An instance is an installation of SQL Server while a database is a collection of data.

Quantity

Another difference between instance and database in SQL server is that there can be multiple instances in a single computer while there can be one or more databases is a single instance.

Types

In a SQL server, there are two types of instances; they are the default and named. Similarly, databases can be system databases and user-defined databases.

Conclusion

The main difference between instance and database in SQL server is that an instance is a copy of the sqlservr.exe executable, which runs as an operating system service while a database is a systematic collection of data that stores data in tables.

Reference:

1. “Database Engine Instances (SQL Server).” Microsoft Docs, Available here.

Image Courtesy:

1. “database” By Sean MacEntee (CC BY 2.0) via Flickr
2. “Sql-server-ce-4-logo” By Microsoft – Microsoft Website (Public Domain) via Commons Wikimedia