SQL Server Expert Blogs
For users to get the information they need from mobile reports, we frequently have to tailor the way we design those reports to the characteristics of the target device. Adam Aspin demonstrates some of the ways that we can deliver easy-to-use Business Intelligence to tablets and smartphones using Reporting Services.
Microsoft 'Always On' technology does not support distributed or cross-database transactions. Why not? Grahaeme Ross shows how to investigate cross-database transactions to understand the problem in more detail, and concludes that a Cross-Database transaction can cause loss of data integrity in the commit phase of the two-phase commit
Access-control within the database is important for the security of data, but it should be simple to implement. It is easy to become overwhelmed by the jargon of principals, securables, owners, schemas, roles, users and permissions, but beneath the apparent complexity, there is a schema-based system that, in combination with database roles and ownership-chaining, provides a relatively simple working solution.
One of the most certain ways of going wrong with any relational database is to get data conversion wrong. Implicit data conversion is a good feature for the expert but can cause a lot of trouble to the unwary. These boil down to seven ways of failing to get data conversion right. Rob Sheldon explains and gives sage advice on how to avoid the problems
With the idea of a generic Dacpac defined by international standard, comes the potential for a Visual Studio developer to use SSDT to create a generic database model to a SQL-92 compliant standard that can then be deployed to any one of the major RDBMSs. The same database model would be deployable to Oracle, MySQL, or SQL Server, for example. Professor Hugh Bin-Haad explains the reasoning and technology behind this.
The job of a DBA requires a fusion of skill and knowledge. To acquire this requires a craftsman mindset. Craftsmen find that the better they get at the work, the more enjoyable the work gets, and the more successful they become. Deliberate practice, Specialization and an appetite for overcoming difficulty are good habits to deliberately adopt to successfully grow those craftsmanlike skills to the point that you become “so good they can’t ignore you”.
More and more applications require the handling of geospatial data. It is easy to store spatial data, but it takes rather more thought to retrieve and manipulate it. Tasks like searching neighborhoods, and calculating distances between points is often required from databases. But how do you start? Roy and Surenda take you through the basics.
Refactoring a database object can often cause unexpected behavior in the code that accesses that object. In this article, adapted from his excellent book, Defensive Database Programming with SQL Server, Alex Kuznetsov discusses several techniques that will harden your code, so that it will not break, or behave unpredictably, as a result such changes.
Spatial Data in SQL Server has special indexing because it has to perform specialised functions. It is able, for example, to break down an indexed space into a grid hierarchy by using a technique called tessellation. This is a rules-based system that, when you compare a shape to an index, works out how many cells in the the grid hierarchy are touched by that shape , and how deep down the grid hierarchy to search. There is powerful magic in Spatial Indexes as Surenda and Roy explain.
It is always bad news if your SQL queries are having to use the SORT operator. It is worse news if you get a warning that sort operations are spilling onto TempDB. If you have a busy, slow TempDB, then the effect on performance can be awful. You should check your query plans to try to eliminate SORTs and never leave a SORT warning unheeded. Fabiano Amorim shows the range of ways of getting information on what is going on with a query that is doing a SORT and when requests are made for memory.
When you're developing database applications, it pays to check for index scans in the SQL Server query plan cache. Once you've identified the queries, what next? Dennes Torres gives some preliminary guidelines on how to find out why these index scans are being chosen for these queries and how to make the queries run faster and more efficiently.
'Temporal' tables contain facts that are valid for a period of time. When they are used for financial information they have to be very well constrained to prevent errors getting in and causing incorrect reporting. This makes them more difficult to maintain. Is it possible to have both the stringent constraints and simple CRUD operations? Well, yes. Dwain Camps patiently explains the whole process.
In order to automate the delivery of an application together with its database, you probably just need the extra database tools that allow you to continue with your current source control system and release management system by integrating the database into it. If you're using the Microsoft stack, then Redgate's tools can help with some of the difficult database parts of the process, as Jason demonstrates.
Database Design is one of those tasks where you have to carefully get all the major aspects right. If you mess-up just one of these, it can all go horribly wrong. So what are these aspects that can ruin database design, and how can you get them right? Robert Sheldon explains.
Behaviour Driven Development is not always clearly understood, and the term is particularly unfamiliar in database circles. Seb Rose introduces us to the fundamentals of BDD, and make some suggestions for how it might be relevant to database development.
Where applications are evolved by gradually molding them to a growing understanding of the business domain, this presents great challenges to database development. If databases are designed too loosely, and initial errors are allowed to fester, the results become harder and harder to refactor until eventually they constitute a database time bomb. Thomas LeBlanc describes how to avoid a few basic, but very common, database time bombs.
How often do you check your query plans during development to see if they contain any warnings? If you're missing them, it means that you're not getting all those hints about missing indexes, join predicates or statistics. Is the query optimiser trying to tell you about implicit conversions? Dennes shows how to view the warnings in plan cache for a particular database using SQL
You can give a deep-dive presentation about SQL Server's transaction log, and round it off by inviting questions. Your audience will stare awkwardly at their boots. Afterwards, to your surprise there will be a queue of questioners, and the questions are the ones they were too shy to ask out loud. Tony Davis answers these apparently simple, yet tricky questions.
A database must be able to maintain and enforce the business rules and relationships in data in order to maintain the data model. It does this through referential constraints. They aren't complex, but are powerful, especially with the means to attach DRI actions to them. Joe Celko explains all, and pines for the ANSI CREATE ASSERTION statement
OLTP databases work best when data that becomes no longer current is then transferred to a separate database for analysis and reporting. There are many ways to do this, but Feodor describes a rapid technique that takes advantage of partitions to automates the rotation of the data and moving it to the analysis server.