I recently worked on a project I which I redesigned sales data warehouse as a STAR schema, using daily file partitions, with a automatic sliding window, and applying data compression at the page level. I ended up reducing a 5 terabyte database to less than 750 GB. I will be writing several articles on the lessons that I learned during the process. Today, I want to talk about how to reseed a identity column if a data load for a dimension fails. Most dimension tables use a surrogate key to…
Tag: SQL Server
Maintenance & History Cleanup Tasks
Today, I will be continuing the series of articles on the control flow tasks available in SQL Server Integration Services (SSIS) to perform Database Administration (DBA) tasks. We will be designing a SSIS package that executes a data retention policy in regards to backup files and [msdb] history records. One of the most important job functions of a DBA is to have a recent backup chain in which a point in time restore can be performed. A backup chain consists of the most recent FULL backup, differential (DIFF) backup, and…
Backup Database Task – Part 2
Tonight, I will be continuing the series of articles on the control flow tasks available in SQL Server Integration Services (SSIS) to perform Database Administration (DBA) tasks. We will be designing a SSIS package that executes a transaction log backup on all user databases and save the results to a directory of my choosing. One of the most important job functions of a DBA is to have a recent backup chain in which a point in time restore can be performed. A backup chain consists of the most recent FULL…
Backup Database Task – Part 1
SQL Server Data Tools (SSDT) is the newest release of the Visual Studio (VS) development environment for the SQL Server projects. I suggest that you use the 2010 VS Shell since the 2012 VS has some GUI color issues that are reminders of terminal screens in the early 1980’s. I hope they listen to developer feedback and fix this issue in a future release. I will be doing a series of articles on the control flow tasks available in SQL Server Integration Services (SSIS) to perform Database Administration (DBA) tasks.…
Deleting Large Data
Most of the time, the transaction log is your friend since it can be used for a point in time recovery. However, when deleting large amounts of data from a database, it can be your enemy. I will be reviewing THREE different TSQL patterns to delete data. Today, we will be using the MATH database that contains prime numbers from 2 to 6 million. I will post the actual files on this article so that they can be detached and reattached as needed for each test. We need to remove…
Checksum vs Hashbytes
I recently worked on a project I which I redesigned sales data warehouse as a STAR schema, using daily file partitions, with a automatic sliding window, and applying data compression at the page level. I ended up reducing a 5 terabyte database to less than 750 GB. I will be writing several articles on the lessons that I learned during the process. Today, I want to talk about how to generate a hash key by using two built in SQL Server functions. A hash function is any algorithm that maps…
Surrogate Keys
I recently worked on a project I which I redesigned sales data warehouse as a STAR schema, using daily file partitions, with a automatic sliding window, and applying data compression at the page level. I ended up reducing a 5 terabyte database to less than 750 GB. I will be writing several articles on the lessons that I learned during the process. Today, I want to talk about how surrogate keys can be used to tie the dimension tables to the fact tables. I need to start the talk off…
Database Files & Objects – Part 4
Today, I will be continuing my talk on database objects that can be viewed through the system catalog views or system stored procedures. A Microsoft SQL Server database is composed of many different objects. We will be investigating how to retrieve information on these objects in the [MATH] sample database. Please see my first article that creates this database. I will be focusing on functions, stored procedures, triggers and views in this article. Let’s use the USE statement to select the sample database.
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<span style="color: #008000; font-size: small;">-- Which database to use. USE [MATH] go </span> |
VIEWS – MSDN QUOTE: “A view…
Database Files & Objects – Part 3
Today, I will be continuing my talk on database objects that can be viewed through the system catalog views or system stored procedures. A Microsoft SQL Server database is composed of many different objects. We will be reviewing how to retrieve information on these objects in the [MATH] sample database. Please see my first article that creates this database. I will be focusing on tables, columns, indexes, and constraints in this article. Let’s use the USE statement to select the sample database.
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<span style="color: #008000; font-size: small;">-- Which database to use. USE [MATH] go </span> |
The most basic component of a database…
Database Files & Objects – Part 2
Today, I will be continuing my talk on database files and database objects that can be viewed through the system catalog views or system stored procedures. A Microsoft SQL Server database is composed of at least two operating system files: a primary data file and a transaction log file. A secondary data files can be used to implement table partitioning or storage of data on different disks by filegroup. If we want to get a simple list of all the databases on the server, one can execute the sp_helpdb system…