The SQL CREATE INDEX statement is used to create clustered as well as non-clustered indexes in SQL Server. An index in a database is very similar to an index in a book. A book index may have a list of topics discussed in a book in alphabetical order. Therefore, if you want to search for any specific topic, you simply go to the index, find the page number of the topic, and go to that specific page number. Database indexes are similar and come handy. Particularly, if you have a huge number of records in your database, indexes can speed up the query execution process. There are two major types of indexes in SQL Server: clustered indexes and non-clustered indexes.
Read more »Ben Richardson
Ben Richardson
Ben Richardson runs Acuity Training a leading provider of SQL training the UK. It offers a full range of SQL training from introductory courses through to advanced administration and data warehouse training – see here for more details. Acuity has offices in London and Guildford, Surrey. He also blogs occasionally on Acuity’s blog
View all posts by Ben Richardson
View all posts by Ben Richardson
Latest posts by Ben Richardson (see all)
- Using SQL CREATE INDEX to create clustered and non-clustered indexes - January 10, 2020
- Rollback SQL: Rolling back transactions via the ROLLBACK SQL query - December 26, 2019
- SQL Injection: Introduction and prevention methods in SQL Server - December 25, 2019
Rollback SQL: Rolling back transactions via the ROLLBACK SQL query
December 26, 2019The rollback SQL statement is used to manually rollback transactions in MS SQL Server.
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SQL Injection: Introduction and prevention methods in SQL Server
December 25, 2019A SQL injection attack is one of the most commonly used hacking techniques. It allows hacks to access information from a database that is otherwise not publically accessible.
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Using sp_executesql stored procedure for executing dynamic SQL queries
December 24, 2019The sp_executesql stored procedure is used to execute dynamic SQL queries in SQL Server. A dynamic SQL query is a query in string format. There are several scenarios where you have an SQL query in the form of a string.
Read more »Understanding the SQL EXCEPT statement with examples
December 23, 2019The SQL EXCEPT statement is one of the most commonly used statements to filter records when two SELECT statements are being used to select records.
The SQL EXCEPT statement returns those records from the left SELECT query, that are not present in the results returned by the SELECT query on the right side of the EXCEPT statement.
Read more »Performing CRUD operations with a Python SQL Library for SQL Server
November 13, 2019This article covers how to connect a Python application to Microsoft SQL Server using a 3rd party Python SQL library. The library that we are going to use is called “pyodbc”, which is freely available. We will use “pyodbc” to perform CRUD (Create Read Update and Delete) operations on a Microsoft SQL Server database.
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SQL DDL: Getting started with SQL DDL commands in SQL Server
November 8, 2019This article explains SQL DDL commands in Microsoft SQL Server using a few simple examples.
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SQL While loop: Understanding While loops in SQL Server
November 6, 2019The SQL While loop is used to repeatedly execute a certain piece of SQL script.
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SQL JOIN TABLES: Working with Queries in SQL Server
November 6, 2019In this article, you will see how to use different types of SQL JOIN tables queries to select data from two or more related tables.
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Dynamic Data Masking In SQL Server
October 15, 2019Security has been one of the prime concerns of database developers since the inception of database management systems. Various data protection schemes have been introduced to provide secure access to sensitive data.
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Working with XML Data in SQL Server
October 11, 2019XML (eXtensible Markup Language) is one of the most common formats used to share information between different platforms. Owing to its simplicity and readability, it has become the de-facto standard for data sharing. In addition, XML is easily extendable.
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Performance Monitoring via SQL Server Query Store
August 19, 2019SQL Server Query Store is a performance monitoring tool that helps us evaluate the performance of a SQL query in terms of several different performance metrics such as CPU and Memory Consumption, execution time and the I/O cycles consumed by the query. Query store is similar to the windows “Task Manager”. A task manager provides information about the CPU, Memory, Network and Disc consumption of a process. Similarly, the Query Store provides insight to similar information.
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Using Logistic Regression in Azure ML for Predicting Customer’s Loan Eligibility
August 19, 2019This article aims to provide the basics of creating Logistic Regression in Azure ML by designing a simple model step-by-step.
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Understanding Graph Databases in SQL Server
August 16, 2019A graph database is a type of NoSQL database that is based on graph theory. Graph databases are ideal for storing data that has complex many to many relationships. In this article, we will study the very basics of graph databases with the help of a simple example.
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Understanding the SQL Server CASE statement
June 28, 2019SQL Server CASE statement is equivalent to the IF-THEN statement in Excel.
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Nested Triggers in SQL Server
March 27, 2019Nested Triggers in SQL Server are actions that automatically execute when a certain database operation is performed, for example, INSERT, DROP, UPDATE etc.
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Python in SQL Server: The Basics
February 13, 2019With the introduction of SQL Machine Learning Services, it is now possible to run Python Scripts from any SQL Server client such as SQL Server Management Studio. In addition to directly running the Python Scripts on SQL Server Clients, you can write Python Code on native Python editors and run it remotely on SQL Server using Python clients for SQL Server.
In this article, we will see how to execute some of the basic Python functionalities within SQL Server Management Studio. The article provides an introduction to running basic Python scripts in SQL Server Management Studio.
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Importing and Working with CSV Files in SQL Server
January 28, 2019Introduction
CSV (comma separated values) is one of the most popular formats for datasets used in machine learning and data science. MS Excel can be used for basic manipulation of data in CSV format. We often need to execute complex SQL queries on CSV files, which is not possible with MS Excel. See this article for what is possible with Power BI.
However, before we can execute complex SQL queries on CSV files, we need to convert CSV files to data tables.
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Machine Learning Services – Configuring R Services in SQL Server
October 25, 2018The R language is one of the most popular languages for data science, machine learning services and computational statistics. There are several IDEs that allow seamless R development. Owing to the growing popularity of the R language, R services have been included by Microsoft in SQL Server 2016 onwards. In this article, we will briefly review how we can integrate R with SQL Server 2017. We will see the installation process and will also execute the basic R commands in SQL Server 2017.
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Difference between Identity & Sequence in SQL Server
August 15, 2018In SQL Server, both the SEQUENCE object and IDENTITY property are used to generate a sequence of numeric values in an ascending order. However, there are several differences between the IDENTITY property and SEQUENCE object. In this article, we will look at these differences.
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Identifying Object Dependencies in SQL Server Management Studio
July 16, 2018In relational database systems, objects have different types of relationships with each other. Apart from table relationships (such as one to one, one to many and many to many), objects such as stored procedures, views, custom functions also have dependencies on other objects. It is important to understand object dependencies, particularly if you want to update an object that depends upon other objects.
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The Difference between CROSS APPLY and OUTER APPLY in SQL Server
June 6, 2018SQL Server supports table valued functions, what are functions that return data in the form of tables.
JOIN operations in SQL Server are used to join two or more tables. However, JOIN operations cannot be used to join a table with the output of a table valued function.
APPLY operators are used for this purpose.
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Understanding SQL Server’s TRY_PARSE and TRY_CONVERT functions
May 16, 2018Data conversion is one of the most fundamental tasks of any programming language. Data received from different sources is often not in the right format. For example, if you receive an XML file where age is in the string format and you want to calculate an average age for the people in the file you will need to convert age into an integer.
To make the conversion process simple, the TRY_PARSE and TRY_CONVERT functions were introduced in SQL Server 2012. Before TRY_PARSE and TRY_CONVERT, SQL Server only had the PARSE and CONVERT functions.
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Understanding the GUID data type in SQL Server
May 3, 2018What is a GUID?
GUID is a 16 byte binary SQL Server data type that is globally unique across tables, databases, and servers. The term GUID stands for Globally Unique Identifier and it is used interchangeably with UNIQUEIDENTIFIER.
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Sequence Objects in SQL Server
March 22, 2018Sequence objects are used to sequentially generate numeric values. They were introduced in SQL Server 2012.
Sequence objects are similar to the IDENTITY column in any SQL table. However, unlike the IDENTITY column, they are independent and are not attached to any table. Sequence objects are used both independently and within the DML statements i.e. INSERT, UPDATE and DELETE.
This article will take a detailed look at sequence objects.
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