First thing first, a little background on triggers. Although often maligned, in certain circumstances they can be very helpful… once you get to know them. For example, sending an email from SQL Server could be done with a trigger based on some anticipated event.
In this article, we will focus on a case with T-SQL data modification when an Insert, Update or Delete statement hits the data in our table. As the name applies the trigger will fire and then we can make decisions on what next based on new data that is coming in or old data that is getting replaced. This is what triggers are most used for.
January 12, 2018
In our case, someone has inadvertently dropped a foreign key from the specific table using the following SQL script which has left our database “broken” and it causing problems with client operations:
January 8, 2018
For every query issued by the application, time is needed to reach the SQL Server and then the time needed for results to get back to the application. As all communication between an application and SQL Server goes via some network (LAN or WAN), network performance could be a critical factor affecting overall performance. Two factors affect network performance: latency and throughput.
December 8, 2017
Working with a database under source control has many benefits. Beside tracking all the changes made against a database, including the information what the changes were and who made them, you can also track history of committed versions of all database objects which can be restored on a database at any point.
However, one of the benefits which will be explained in this article is comparing and syncing two copies of the same database. Using ApexSQL Source Control, all objects that are missing in one copy of a database can be created/restored in the second copy of a database, preserving the integrity of both databases.
December 7, 2017
There are thousands of distributed. commercial software applications aka shrink-wrapped, from small shareware apps to large corporations, that use a SQL Server backend. These systems, although distributed, could often benefit from and sometimes require data change auditing at the client location.
Although ApexSQL sells a successful, enterprise auditing tool for SQL Server, ApexSQL Audit, this tool is often not appropriate for distributed, commercial software.
November 29, 2017
There is a maxim that comes from the world of Python programming: “There should be one – and preferably only one – obvious way to do it.” (See The Zen of Python) in the references. While that is a good goal for any language, it is a difficult goal to achieve. T-SQL is no exception here!
Consider a simple problem: You have a customer transaction table with dated rows. You are asked to produce a list of the top transactions per day. “Top” could be defined as the one with the most items, the highest value, the most important customer or a variety of other criteria. However, you define it, at some point, you will want the maximum (or minimum) value of one of the columns. Then you will want to output the entire row (or rows, in the case of a tie) matching that value. Sounds simple, right? Well, it actually is simple, but the number of ways to do it may surprise you!
November 22, 2017
One of the many tasks of the DBA in charge on a development project is to make sure the team stays consistent in their code. Routine checks for SQL best practices such as naming conventions, right data types usage, problematic things like cursors, potentially fatal things like Deletes without Where clauses can cause a lot of headaches.
November 10, 2017
A clustered index is critical to performance on any table. Not only does it dictate the logical storage of data for the entire table, but it also is the index that all others will reference when additional data is required. A poorly chosen clustered index can greatly hamper performance, causing latency, contention, and excessive IO. In this article, we will explore clustered indexes, and use ApexSQL Tools to assist in identifying those that could be improved upon.
November 9, 2017
Creating a foolproof disaster recovery solution is imperative for every business. After the Recovery Point Objective (RPO) and Recovery Time Objective (RTO) are defined, a database backup plan should be created to match these objectives. Most DBAs tend to automate the majority of tasks related to database backup plans. Regular database backup schedules are set in order to create continuous backup chains, that can later be used to recover a database in the case of a disastrous event. By setting the backup schedule, the continuity of the backup process is ensured, and most of the job is performed automatically on a regular basis.
November 7, 2017
This article explains how SQL database source control can help in version control SQL scripts alongside SQL database objects. Developing a software sometimes requires versioning not only database objects, but custom SQL scripts for migration, configuration, automation or other purposes
November 3, 2017