Tag: SQL Server

Table Partitioning in SQL Server – Partition Switching

This post is part 2 of 2 in the series Table Partitioning in SQL Server

Partition SwitchingInserts, updates and deletes on large tables can be very slow and expensive, cause locking and blocking, and even fill up the transaction log. One of the main benefits of table partitioning is that you can speed up loading and archiving of data by using partition switching.

Partition switching moves entire partitions between tables almost instantly. It is extremely fast because it is a metadata-only operation that updates the location of the data, no data is physically moved. New data can be loaded to separate tables and then switched in, old data can be switched out to separate tables and then archived or purged. All data preparation and manipulation can be done in separate tables without affecting the partitioned table.

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Using a Numbers Table in SQL Server to insert test data (T-SQL Tuesday #65)

T-SQL TuesdayT-SQL Tuesday #65 is hosted by Mike Donnelly (@SQLMD). There is no specific topic to write about this month, Mike simply wants us to learn something new and then write a blog post to teach it to others. I want to share something that I only recently learned, something I wish I had known about years ago, something that became part of my toolbox as soon as I discovered it: the Numbers Table. It is so simple and solves so many problems that everyone should know about it :)

A Numbers Table (perhaps most known as a Tally Table, sometimes called an Auxiliary Table of Numbers and even referred to as the Swiss Army Knife of SQL Server) is a one-column helper table that contains the numbers 1, 2, 3, 4, 5 and so on all the way up to the-highest-number-you-could-possibly-need.

It can be used to replace slower loops and row-by-row operations with faster set-based operations, generate dates, split strings, find gaps in data sets, expand data sets, insert test data and probably hundreds of other things. There are so many great and detailed articles already published about this topic, so I will stick to the T-SQL Tuesday topic of “Teach Something New” and share the two most recent things I learned: different ways to create a numbers table, and different ways to quickly insert test data by using a numbers table.

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Table Partitioning in SQL Server – The Basics

This post is part 1 of 2 in the series Table Partitioning in SQL Server

SQL Server Table Partitioning Cheat SheetThere are many benefits of partitioning large tables. You can speed up loading and archiving of data, you can perform maintenance operations on individual partitions instead of the whole table, and you may be able to improve query performance. However, implementing table partitioning is not a trivial task and you need a good understanding of how it works to implement and use it correctly. Table Partitioning is an Enterprise Edition feature only.

Being a business intelligence and data warehouse developer, not a DBA, it took me a while to understand table partitioning. I had to read a lot, get plenty of hands-on experience and make some mistakes along the way. (The illustration to the left is my Table Partitioning Cheat Sheet.) One of my favorite ways to learn something is to figure out how to explain it to others, so I recently did a webinar about table partitioning. I wanted to follow that up with focused blog posts that included answers to questions I received during the webinar. This post covers the basics of partitioned tables, partition columns, partition functions and partition schemes.

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Table Partitioning Webinar for Pragmatic Works

Pragmatic WorksPragmatic Works hosts and records free webinars every Tuesday and Thursday, called Free Training on the T’s. In March 2015 they wanted to highlight Women in Tech (WIT) by hosting nine webinars with speakers from the SQL Server community. I was very honored and excited to be invited, and a little nervous since it was my first ever webinar.

The recording of my webinar Table Partitioning in SQL Server: A Magic Solution for Better Performance? is now available, and the slide deck is available on my SlideShare:

The introduction was not included in the recording, but it can be summed up as “thank you to Pragmatic Works for supporting WIT, thank you for attending my webinar, my name is Cathrine and this is an introduction to table partitioning” :) There were some technical issues so the sound is missing for about a minute in the middle of the webinar, and I couldn’t see any questions in the chat. To all of you who asked questions, I’m sorry for not answering during the webinar, but I have now received the transcript and will answer your questions in upcoming blog posts.

Upcoming blog posts
Ed Leighton-Dick (@eleightondick) recently announced a #SQLNewBlogger challenge where those who participate will write one blog post every week in April. I have decided to participate in this challenge, and I encourage everyone else to do the same! :) I got a lot of great questions during my webinar that I want to answer in more detail with scripts, step-by-step instructions and pictures, so I have picked Table Partitioning as my topic for the challenge. You can find all the blog posts in the Table Partitioning in SQL Server Archive, and check back every week in April if you want to learn more about Table Partitioning basics! :)

SQL Server, SSIS and Biml Data Types

This post was first published on May 27th, 2014, and was last updated on July 16th, 2017.

SQL Server, SSIS and Biml Data TypesThe table below shows a simplified mapping between SQL Server, SSIS and Biml data types. The table does not include all possible mappings or all data types, but is meant as a quick reference while developing and learning Biml. It was mainly created as a cheat sheet for myself, but I hope other Biml developers will find it useful :)

(Pssst, if you want to link to this post, you can use this prettier link: https://www.cathrinewilhelmsen.net/BimlDataTypes. Thanks!)

There are some problems mapping certain data types automatically between SQL Server, SSIS and Biml. Different providers and Biml methods will produce different data mapping results. I have written about the problems and differences I have encountered below.

All columns are sortable:

SQL ServerSSISBiml
bigintDT_I8Int64
binaryDT_BYTESBinary
bitDT_BOOLBoolean
charDT_STRAnsiStringFixedLength
dateDT_DBDATEDate
datetimeDT_DBTIMESTAMPDateTime
datetime2DT_DBTIMESTAMP2DateTime2
datetimeoffsetDT_DBTIMESTAMPOFFSETDateTimeOffset
decimalDT_NUMERICDecimal
floatDT_R8Double
geographyDT_IMAGEObject
geometryDT_IMAGEObject
hierarchyidDT_BYTESObject
image (*)DT_IMAGEBinary
intDT_I4Int32
moneyDT_CYCurrency
ncharDT_WSTRStringFixedLength
ntext (*)DT_NTEXTString
numericDT_NUMERICDecimal
nvarcharDT_WSTRString
nvarchar(max)DT_NTEXTString
realDT_R4Single
rowversionDT_BYTESBinary
smalldatetimeDT_DBTIMESTAMPDateTime
smallintDT_I2Int16
smallmoneyDT_CYCurrency
sql_variantDT_WSTRObject
text (*)DT_TEXTAnsiString
timeDT_DBTIME2Time
timestamp (*)DT_BYTESBinary
tinyintDT_UI1Byte
uniqueidentifierDT_GUIDGuid
varbinaryDT_BYTESBinary
varbinary(max)DT_IMAGEBinary
varcharDT_STRAnsiString
varchar(max)DT_TEXTAnsiString
xmlDT_NTEXTXml

(* These data types will be removed in a future version of SQL Server. Avoid using these data types in new projects, and try to change them in current projects.)

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