Get Filestream Storage Directory

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Filestreams are a great way to store files in SQL Server. SQL Server makes this super easy by managing the storage of the physical files on the file system. But what if you want to get access to these files or if you want to know where they are stored. SQL Server wants you to access these files through a network share managed by SQL Server. They provide a function called PathName that you can call to get this path. You will call this function like you would call an extension method in .Net. In the example below, we will assume that the column InvoiceFile is a Filestream datatype. We call the PathName() function to get the share name to where the files are stored.

Estimate Backup Size In SQL Server

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When you’re creating your database backup maintenance plans, you need to choose a drive that has enough space for your backup. So how much space will you actually need to backup your database? Figuring this out is actually a lot easier than you would expect.

Although nothing will be 100% accurate, SQL Server has a built in stored procedure for calculating the used space in a database. A full database backup only stores the actual data/objects in the database. The unused space is not stored.

In the example above we call the sp_spaceused stored procedure from the database that we would like the size from. This is important… you need to execute this from the database that you want to get the size for. This will return a dataset with multiple columns. The column that you will look at is the reserved column. This will show the amount of space without the unused space.

 
Note
The @updateusage parameter tells the stored procedure to update the space usage info before returning the used size. Passing TRUE in to this parameter will give us the most accurate size estimate.

Varchar Vs Nvarchar

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People often want to know the difference between varchar vs nvarchar. If you are new to nvarchar, I don’t blame you for not understanding the difference… as they are very similar.

The major difference is that nvarchar stores data as Unicode, where varchar does not. This uses more space, but provides flexibility to handle foreign characters that would not fit in a varchar field.

 
How Varchar And Nvarchar Are Similar

  • They are both used to store text/string data in them
  • The amount of space that both use depends on the size of the data that you are putting in it. It grows with every character that you store.

 
How Varchar And Nvarchar Are Different

  • Nvarchar stores data as Unicode. Varchar stores data as non-Unicode.
  • Varchar stores data at 1 byte per character. Nvarchar stores data at 2 bytes per character.
  • Varchar supports up to 8000 characters in the field definition. Nvarchar only supports up to 4000 characters. Varchar(max) and nvarchar(max) not included.

 
My Thoughts On Which One To Use
Where I am at, I deal with a lot of data. Although it would be nice to be able to support all foreign characters in the database, it is likely that I will never get it. My philosophy is that unless you need to support these extended Unicode characters, just make the field varchar. Nvarchar uses double the space as varchar. Unless your business has a requirement for this, just save the space.

SQL Server Rename Column

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This article will cover how to rename a column in SQL Server. The function of a SQL Server rename column is not performed too often. Usually we do this when we roll out a new product and we want to make a column more generic.

 
SQL Server Rename Column (SQL Server 2005 and beyond)

They make this super simple. Just remember to put to single quotes around the parameters.

The above SQL Server rename column code snippet has a few parts to it. Here is the breakdown:

  • sp_rename – This is a system stored procedure will rename different types of objects in SQL Server.
  • ‘Animals.AnimalName’ – This is the tablename and column that I would like to rename.
  • ‘AnimalRealName’ – This is the new name that I would like to call the column.
  • ‘COLUMN’ – This is the type of object that you would like to rename is. To rename a column, always leave this value ‘COLUMN’.

 
If you would like to know how to do a SQL Server rename column for SQL Server versions prior to 2005, please leave a note in the comments.

 
 
Reference: http://msdn.microsoft.com/en-us/library/ms188351(v=sql.90).aspx

SQL Server 2014 Feature – Non-Clustered Indexes For Table Variables

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This is truly an amazing feature to add to SQL Server 2014. I use table variables all the time and this was the only thing I didn’t like about them. Up to this point, SQL Server did not support having non-clustered indexes on table variables (the one with the name that starts with the @). If you wanted to do this, you had to create/use a temp table (the one with the name that starts with #).

With SQL Server 2014, they changed this and now allow the table variables to have non-clustered indexes as well. To do this, we simply add a little bit of extra code after the column declaration.

In the sample above, we create a table variable called @AnimalTableVar. Then when we declare the column AnimalName, we add an index called IX_AnimalTempTable_AnimalName.

Here is how selecting from this table shows up in the execution plan!
Non-Clustered Indexes For Table Variables

Reference: http://msdn.microsoft.com/en-us/library/ms188927(v=sql.120).aspx