Articles tagged SQL

SQL GROUP BY Basics

It sometimes pays to go back and look at what you think you already know about SQL. Joe Celko gives a quick revision of the GROUP BY and HAVING clauses in SQL that are the bedrock of any sort of analysis of data, and comes up with some nuggets that may not be entirely obvious… Read more

SQL Server System Views: The Basics

When maintaining or refactoring an unfamiliar database, you'll need a fast way to uncover all sorts of facts about the database, its tables, columns keys and indexes. SQL Server's plethora of system catalog views, INFORMATION_SCHEMA views, and dynamic management views contain all the metadata you need, but it isn't always obvious which views are best to use for which sort of information. Many of us could do with a simple explanation, and who better to provide one than Rob Sheldon?… Read more

The SQL Server 2016 Query Store: Accessing Query Store Information Using DMVs

The SQL Server 2016 Query Store provides several new ways of troubleshooting queries, studying their plans, exploring their context settings, and checking their performance metrics. In using the Query Store to ensure that performance is as good as possible, it isn't long before it becomes important to be familiar with the DMVs that are associated with the query store, and using them in custom queries.… Read more

Maintaining T-SQL Code Quality Using SQL Code Guard

Sometimes you need some functionality in your database build process that isn't quite available. Visual Studio Database projects don't have great ways of reviewing SQL code for potential errors, but is it possible to adapt a good command-line tool like SQL Code Guard that does the job well? Lukasz shows how to do it by using NuGet packages to integrate such tools with the project and the build process.… Read more

The SQL Server 2016 Query Store: Built-in Reporting

One of the most important features of the SQL Server 2016's new Query Store is the reporting. With these features, it is now possible to get a wealth of information on how your query workload is performing, either aggregated for the entire query workload or for a single query. With this information, you can see the effects of 'forcing' an execution plan for specific queries and get feedback of the consequences.… Read more

Wherever I Lay My Hat: Release Management in TeamCity with Redgate DLM

Where you have multiple services, applications and databases in your environment, and perhaps with high levels of scrutiny and governance, you'll probably want a Release Management system for deploying database and application code together: You can, alternatively, use a separate Release Management component. But for simpler applications, you can use your existing build system such as TeamCity to deploy changes. Using a database deployment example, Richard Macaskill shows how.… Read more

Microsoft Azure DocumentDB

DocumentDB is a late-entrant in the Document-oriented database field. However, it benefits from being designed from the start as a cloud service with a SQL-like language. It is intended for mobile and web applications. Its JSON document-notation is compatible with the integrated JavaScript language that drives its multi-document transaction processing via stored procedures, triggers and UDFs.… Read more

JSON support in SQL Server 2016

At last, SQL Server has caught up with other RDBMSs by providing a useful measure of JSON-support. It is a useful start, even though it is nothing like as comprehensive as the existing XML support. For many applications, what is provided will be sufficient. Robert Sheldon describes what is there and what isn't.… Read more

Declarative SQL: Using References

There are several ingenious ways of using SQL References to enforce integrity declaratively. Declarative Referential Integrity (DRI) is more effective than using procedural code in triggers, procedures or application layers because it uses the SQL paradigm, thereby making optimisation easier and providing clearer expression of the rules underlying the data.… Read more

Declarative SQL: Using UNIQUE Constraints

In SQL, you can express the logic of what you want to accomplish without spelling out the details of how the database should do it. Nowhere is this more powerful than in constraints. SQL is declarative, and Joe Celko demonstrates, in his introduction to Declarative SQL, how you can write portable code that performs well and executes some complex logic, merely by creating unique constraints.… Read more

The PoSh DBA – Using the Basic PowerShell Paradigms

PowerShell is like any computer language: you must understand the paradigms, the constructs, and the way it is designed to work to get the most value from it. It is no good just translating 'sausage-string' procedural algorithms. To demonstrate how PowerShell should be used as its' creators intended, Laerte Junior shows the difference between PowerShell problem-solving with, and without, PowerShell paradigms.… Read more

Jodie Beay and the Production Database Drift

You make an example database, like NorthWind or WidgetDev in order to test out your deployment system and the next thing you know you're worrying about constraints, backup and security. Then you add an index to the production system and feel a pang of guilt. What would the Devs say? Somehow databases take on lives of their own, populated by the lost souls of users, Developers and DBAs. Has the Redgate DLM Team's practice Forex database somehow come alive?… Read more

Doing a SQL Server Healthcheck via PowerShell

PowerShell is an ideal tool for doing health checks of a collection of SQL Server instances, and there are several examples around, but few acknowledge the fact that individual DBAs have their own priorities for tests, and need something easily changed to suit circumstances. Omid's health check allows tests to be SQL or PowerShell and requires only adding, altering or deleting files in directories. … Read more

The SQL Server 2016 Query Store: Overview and Architecture

SQL Server's Query Store, introduced in SQL Server 2016, helps to troubleshoot query performance by capturing a range of information about query usage, CPU, memory consumption, I/O and execution time, and retaining every Execution Plan for analysis. Much of this information is available through queries. It looks set to be the most significant enhancement of SQL Server 2016.… Read more