General database design

Ahmad Yaseen

Database checkpoints – Enhancements in SQL Server 2016

September 21, 2016 by

When a new row is inserted or an existing one is updated in your database, the SQL Server Database Engine will keep that change in the buffer pool in the memory first, without applying each change directly to the database files for IO performance reasons. These data pages located in the buffer pool and not reflected yet to the database files are called Dirty Pages. The SQL Server Database Engine uses a special kind of processes to write these dirty pages to the data and log database files periodically. These processes are called Checkpoints. The Checkpoint creates a mark that is used by the SQL Server Database Engine to redo any transaction that is committed, written to the database transaction log file without reflecting the data changes to the data files due to an unexpected shutdown or crash. Also, this recovery point that is created by the Checkpoint will be used to roll back any data changes associated with uncommitted transaction, by reversing the operation written in the transaction log file. In this way the SQL Server Engine will guarantee the database consistency. The time that is taken by the SQL Server Database Engine to redo and undo the transactions is called the Recovery Time. All information about the Checkpoints will be written to the database boot page to identify till which point the database files are synchronized with the buffer pool when the system wakes up after crash or shutdown.

Read more »
Ahmad Yaseen

Optimize NULL values storage consumption using SQL Server Sparse Columns

August 29, 2016 by

SQL Server 2008 introduces a new column attribute that is used to reduce the storage consumed by NULL values in the database tables. This feature is known as Sparse Columns. Sparse Columns work effectively in the case of the columns with high proportion of NULL values, as SQL Server will not consume any space storing the NULL values at all, which helps in optimizing the SQL storage usage.

Read more »
Jean-Pierre Voogt

The new SQL Server 2016 sample database

July 22, 2016 by

Background

We have all learned to love and hate the trusty Bike shop database. Almost every demo or presentation pertaining to SQL Server we do, we use the AdventureWorks sample database. Almost every code sample on books online references AdventureWorks for illustrations and practical explanations of a feature. When SQL Server 2005 was released Microsoft replaced the old Pubs & Northwind Sample databases with a more complete and more feature rich database called AdventureWorks. Ever since we have been using this new sample database for almost everything we want to test. Microsoft has now given us an even better sample database called WorldWideImporters, which utilises almost every SQL Server feature I can think of from Temporal Tables to In-Memory table.

Read more »
Ahmad Yaseen

SQL Server 2014 contained databases

June 1, 2016 by

SQL Server provides two ways to authenticate users; SQL Server Authentication, which requires a predefined username and password to connect to the SQL Server, and Windows Authentication, in which SQL Server trusts the windows integrated user. The server level user that is authenticated to connect to the SQL Server is called a Server Login. This login should be mapped to a database user and granted permissions at the database level in order to access the database and be able to perform the authorized tasks. The relationship between the Server login and the database user in addition to the database metadata stored in the master system database draw up the dependencies between the SQL Server databases the server-level resources.

Read more »
Rajendra Gupta

Database snapshot in SQL Server

January 28, 2016 by

Database snapshot is a great feature that offers virtual read only consistent database copy. When we create the database snapshot in the live operational database, it takes a database point in time static view and Rollback all uncommitted transactions in the snapshot database so we will not be having any inconsistent data that is yet to be committed. Database snapshot always exists on the Source database server.

Read more »
Rajendra Gupta

Contained databases in SQL Server

January 12, 2016 by

As we know there are two types of authentication available in SQL Server Windows authentication and SQL authentication. In Windows authentication we use Active directory authentication to connect with SQL Server which makes the most secure authentication method as it can have complexity, group policy configured at AD level applied to all domain servers while in SQL Authentication SQL users are created inside SQL and provided required permissions. The Permissions includes server wide and database wide. The logins can have certain permissions at the database level might be read or write etc.

Read more »
Sifiso W. Ndlovu

SQL Server lessons from a TFS installation

January 8, 2016 by

Introduction

More often than not (at least in places I’ve worked at), the job of installing, configuring and subsequent administration of Team Foundation Server (TFS) is performed by different individuals to those administering enterprise applications such as Windows Server, SQL Server, SharePoint etc. This is because TFS, unlike other enterprise applications, often has to be administered from both the server side (i.e. TFS Administration Console) as well as the client side (i.e. using Team Explorer in Visual Studio) – it is thus not surprising that a TFS administrators may once had been a developer. The benefit of having a TFS administrator with a software development experience is that it may be easy to get developer-buy-in into the tool. However, the disadvantage to this is that developers usually get accustomed to doing things in a certain way – like connecting to SQL Server using (local) convenience names.

Read more »
Ed Pollack

Data boundaries: Finding gaps, islands, and more

January 6, 2016 by

One of the more difficult challenges we face when analyzing data is to effectively identify and report on boundaries. Data sets can contain any number of significant starting and stopping points that may indicate significant events, such as missing data, important business events, or actionable changes in usage. Regardless of the use case, knowing how to quickly locate and manage data boundaries is extremely useful. Knowing how to design solutions that can effectively avoid these scenarios can also be helpful in the long run.

Read more »
Pinal Dave

SQL Server: Lock settings to use to enhance partitioning capability

December 30, 2015 by

When talking about performance and scalability inside SQL Server, I don’t see anyone missing out on the fact to mention how locks get involved. I often see DBA’s complain to developers that their code is not scalable and they are experiencing heavy locks in the system because of the way the code has been written. The more I work with SQL Server, the more I start to understand some of these nuances.

Read more »
Ahmad Yaseen

Best practices after installing Microsoft SQL Server

December 15, 2015 by

Introduction

Working as a DBA, the simplest task requested from you is installing SQL Server. As a start you will check the server’s hardware and software specs to make sure that you can start the installation, checking which services will be installed and the security authentication type required. After this pre-installation plan, you will start the normal installation process.

After completing the installation, you need to apply specific configurations on the server to make sure that the server can host production databases and the users can connect to it successfully.

In this article, I will describe the common configurations that you should apply after the SQL Server installation.

Read more »
Murilo Miranda

Using SMB fileshare as a storage alternative

January 16, 2015 by

Do you know that you can store system and user databases in a fileshare? Even for a clustered instance this is an option now. In this article we will check how to implement this solution.

On the latest versions of SQL Server new possibilities to assign storage to a clustered instance became available. In this article, we will talk about one of these options, which is also an option for standalone instances by the way: The network-attached storage – SMB Fileshare.

Read more »
Daniel Calbimonte

SQL Server Database Snapshots

October 30, 2014 by

Introduction

MS SQL Server 2005 and later versions include the Database Snapshot feature to have snapshot of the database for reports, as a copy in different periods.

The Database Snapshot can be created multiple times and it can only be created using the T-SQL.

In this article, we will show how to create a Database Snapshot, how to see the snapshot created in the SQL Server Management Studio (SSMS), how to recover objects dropped or data removed using the snapshot. Read more »

Sifiso W. Ndlovu

Introduction to pagination in SQL Server

May 12, 2014 by
Microsoft SQL Server distinguishes between paging and pagination. Paging refers to handling of memory bottlenecks whereas pagination, the focus of this article, refers to dividing T-SQL query result set into discrete parts. The general concept of Pagination is prevalent in various professional disciplines (i.e. journalism, publishing, web development etc.). According to Wikipedia Pagination is the process of dividing content (i.e. website search results, newspaper article etc.) into separate yet related pages. The major benefit to such dividing of content is usually a cleaner and clearer structuring of content which enhances the reading (or browser-navigation) experience to the consumer of such content. Read more »
Sifiso W. Ndlovu

Sequence objects feature in SQL Server

April 24, 2014 by

Introduction to Sequences

Sequence is a new object that was introduced in SQL Server 2012 for a key-generating mechanism. It has been made available across all editions of SQL Server 2012. It was added as an alternative to IDENTITY columns feature that has been prevalent in the previous versions of SQL Server. Despite being newly introduced in SQL Server 2012, sequences have long been prevalent in other database platforms such as Oracle and IBM’s DB2. Thus, the data migration into SQL Server 2012 from other database platforms is now more convenient and simplified.
Read more »