Database design

Kaloyan Kosev

How to work with filegroups in SQL Server and migrate data between them

March 8, 2017 by

As you may already have figured out, the default settings in SQL Server are not always the best. Such is the case when you are working with new user databases; usually you get a single data (*.mdf) and transaction log (*.ldf) file. The data file resides within the PRIMARY file group; the only one we have so far, and it will store all of our databases objects, system objects, user tables, user stored procedures and all other objects. In some cases this default configuration may be good enough for you, but let us cover why would you prefer a different configuration in your production environment.

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Daniel Calbimonte

Are SQL Server database triggers evil?

January 25, 2017 by

Introduction

There is a lot of talk about how bad triggers are, how you should never use them, etc. I wanted to spend some time reviewing fact vs fiction and do an objective analysis of SQL Server database triggers (both DDL and DML), warts and all. We will review alternatives and compare them with triggers to determine advantages vs disadvantages of each approach.

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Best Practices for Configuring Newly Installed SQL Server Instances

January 20, 2017 by

Often we install SQL Server on clients or we get to clients where they have pre-installed SQL Server Instances. As a DBA we have the Primary responsibility of keeping the Database Up and Running. This responsibility leads to optimizing, performance tuning and many other stuff related to database’s internal objects. While keeping the other aspects in mind many of us have to go through the configuration of the newly installed or pre-installed but un-configured instances. Configuring SQL Server newly instances are not an easy task and a DBA might want to configure an Instance in many ways.

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Kimberly Killian

How to Split a Comma Separated Value (CSV) file into SQL Server Columns

December 29, 2016 by

Receiving a comma delimited file is not new technology nor is it difficult to deal with in SQL Server. As a matter of fact, it is extremely easy. There are many cases as to why you would want to do this. For example, you have an external data source that needs to be imported into your database/table. There a couple ways to do this, however the quickest and easiest way is to use the native “import” feature within SQL Server Management Studio and you can even save it to an SSIS Package at the end of the process. The end result of using this method is that the external CSV file is loaded into a SQL Server table where columns are created and rows are populated.

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Daniel Calbimonte

FAQ about Dates in SQL Server

December 22, 2016 by

Introduction

In this article, I compiled a list of FAQs and Answers about dates.

  1. Which function should I use to get the current date in SQL Server?
  2. How can I get the current time in the format hh:mm:ss?
  3. How can I calculate my age in SQL Server with a birth date?
  4. How can I insert the current time by default in a SQL Server table?
  5. How can I check the total time that the employees of my company worked per day?
  6. How can I get the time of a specific region?
  7. How can I get the time of a specified Standard time?
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Ahmad Yaseen

Understanding the SQL Server Proportional fill algorithm

November 22, 2016 by

When creating a database, SQL Server maps this database with minimum two operating system files; the database data file MDF and the database log file LDF. Logically, the database data files are created under a collection set of files that simplifies the database administration, this logical file container is called the Filegroup. Database data files can come in two types, the Primary data files that contains metadata information for the database and pointers to the other database files in addition to the data, where each database should have only one Primary data file and the optional Secondary files to store data only. The basic storage unit in SQL Server is the Page, with each page size equal to 8KB. And each 8 pages with 64KB size called Extent.

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Aamir Syed

Have your database server talk to you: Send emails directly from SQL Agent Jobs

November 7, 2016 by

Recently, I was asked if I can write and run a specific query and have the results, (if any) emailed to a specific group of people every day? But only send the email if the query returns results. Who wants to open and empty email after all?

As with any DBA, we need a way to automate this process, as our time is valuable. Who wants to manually run a script, paste it into excel and then email it directly to users every morning?

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Ahmad Yaseen

SQL Server 2016 Database Scoped Configuration

October 21, 2016 by

SQL Server 2016 introduces a new set of configurations that can be applied at the database level to control its performance and behavior. These configurations were previously applicable only at the SQL instance level before version SQL Server 2016, With the ability to configure settings at the database level, many databases that are hosted in the same instance can now be isolated from each other, with each database has its own customized configurations. The database level configurations allow us also to set different database configurations for the Always On Availability Groups primary and secondary databases to meet the different types of workloads.

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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.

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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.

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