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Page Revision: 2011-05-23 04:24

Overview

This is a homebrew SQL (T-SQL) formatter, mainly created because I could not find any free and open-source T-SQL formatters that handle T-SQL exactly the way I want, including full stored procedure formatting.


It's written in C#, and designed to work in three phases, each using a pluggable class:

• Tokenization - text-level parsing, identifying operators vs keywords vs whitespace vs comments, etc
• Parsing - keyword-level parsing, identifying hierarchical relationships between components of the T-SQL code, statements, clauses, blocks, flow control, etc.
  • Please note, this is not a fully-fledged SQL parser. It does not distinguish between different types of DML, it does not parse full expression trees, etc - there's a lot it doesn't do, it just does the bare minimum to enable the formatting I was aiming for.
• Formatting - turning the SQL parse tree back into T-SQL code, with customizable formatting preferences including HTML colorizing.
  

The main portion of the project is a .Net 2.0 library. However, a number of smaller sub-projects expose the library for use in different ways:

• An SSMS Addin that allows you to format the current file or selected text with a single hotkey
• A command-line utility that lets you format any number of files in bulk
• A Winforms demo app that lets you look at the token stream and parse tree
• A Web Service that exposes the same functionality across http, used in the demo below
  

The library is largely complete, but undocumented. For the list of known issues, please see the readme file. As there is only as much parsing detail as necessary to support the desired formatting, the parse tree format is still not finalized; many formatting enhancements require new elements in the parse tree.

The code is hosted on GitHub at https://github.com/TaoK/PoorMansTSqlFormatter; I'd be very grateful for any feedback on the functionality, the code or any other aspect of the project!

License / Redistribution

The library and accompanying programs are released under the Affero GPL. This means that you are allowed to make any changes you want, there are restrictions/requirements attached only if you choose to redistribute the original or modified code: If you choose to redistribute/expose the functionality, then you must make the source available to the recipients/users (even of a web service). For private usage, you can make any changes you want and never need to tell anyone; if you distribute the app/functionality or a service that relies on it, then you must also distribute the source. For more details, please see the AGPL article on wikipedia or at the source, the FSF (free software foundation).

At least for the moment (as I'm the only one who has contributed to the project so far), the project could be dual-licensed if you really, really wanted to use it in a commercial program. If so please contact me, I'm sure we could work something out.

Download

Ready-to-run:

• SSMS Add-In (setup program):
• WinForms Demo App (simple exe): SqlFormatterWinForms.0.9.8.zip
• Command-line bulk formatting utility (simple exe): SqlFormatter.0.9.8.zip
  

Compiled Library:

• SqlFormatterLibrary.0.9.8.zip
  

Source:

• Please download from github at https://github.com/TaoK/PoorMansTSqlFormatter. If this is impractical for whatever reason please contact me, and I'll make the source available by some other mechanism.
  

Change Log:

• See the changelog on github for recent changes.
  

Demo

Paste some T-SQL here (then leave the textbox):

And it will be formatted here:


Please note (1): This demo uses some default default values for formatting options supported by the library. For a more complete customizable demo, please download the windows forms app (sorry, I haven't compiled and made that available here yet - coming soon; in the meantime, you can download the source from github).

Please note (2): This demo does send the SQL that you input to the webserver, because the library is implemented as C# and I didn't feel like messing around with silverlight. I am not doing any logging of request content, however, and as far as I know my hosting provider isn't either - so your SQL code should be as reasonably private as anything you post in an online (non-SSL) form. You can see the formatting web service code on github, and you can see the submission code in the source of this page, it's just some simple jQuery code.

Please note (3): this library is released under the GNU Affero GPL v3, so third parties can feel free to host it as well, if they make available the source of the version that they are hosting (see the detailed terms of the AGPL, eg on wikipedia).

But Why??

You may wonder why create yet another SQL formatting library... I've asked myself that a few times as I've been working on this. One answer is that it is fun, and I think I can do a pretty good job, at least to suit my requirements, and I've learned quite a lot about T-SQL in the process. Another reason is that when I have searched for this in the past, I've never found a tool that did exactly what I wanted to. Finally, I hadn't found any open-source library that I thought I could help improve, rather than starting my own.

The main challenge, I believe, is that I want to do full re-formatting of any T-SQL code, supporting all keywords and syntax constructs. Do do this with a full T-SQL parsing model would be difficult, or maybe even unrealistic, to achieve in a one-man open-source project. By scaling it back to a partial parsing model where only formatting-relevant constructs are singled out, the scope of the project is significantly reduced, hopefully to an achievable and maintainable level.

Other Products and Projects

To get a better idea of the value of this project (for myself and potentially others), I plan to put together a quick comparison table for this project vs any other products and projects I come across. Obviously I will try to avoid undue bias, and equally obviously I will still be biased towards this project :).

Here is the list of all T-SQL formatting tools I've encountered. A comparison table will be coming later:

• SqlFormat .Net 3.5 Formatter Library: The only open-source tool I've found out there. The project aims are different to this one, as they indent to create a full parse-tree for those parts of the language that are supported. As such, only a reasonably small subset of language features are covered at present - primarily those used in Entity Framework-generated SQL.
• GuDu Software options:
  • Instant SQL Formatter: Online-only free tool
  • OracleFAQs SQL and PL/SQL Formatter: appears just to be an externally-hosted copy of the "Instant SQL Formatter" tool
  • SQL Pretty Printer: Trialware SSMS add-in
  • General SQL Parser: Like it says... Trialware general SQL parser
• T-SQL Tidy: Online-only free tool, with free webservice and ssms add-in (webservice-based)
• Red Gate options:
  • Red Gate Simple-Talk Code Prettifier: Free online-only tool
  • Red Gate SQL Prompt: Trialware code/name completion, exploration and formatting tool
• SQLInForm options:
  • SQLInForm Free Online Version: Crippled online-only java applet-based tool (100 lines)
  • SQLInForm Desktop or Server Version: Java-based tool
• manoli.net c# code format: Apparently does T-SQL too
• Navicat Lite: DB Management tool with free/lite version for non-commercial use, apparently includes a sql beautifier in the lite version
• RazorSQL Trialware DB Management tool that apparently includes some formatting functionality
• DevArt SQL Complete: SSMS add-in with free version (?) that supports formatting
• UBitSoft options
  • T-SQL Beautifier: Online-only free tool
  • SQLEnlight: Trialware SSMS Add-in with code formatting and analysis / rule validation
• SoftTree SQL Assistant: Another trialware code completion and formatting tool, supporting multiple editors and multiple SQL dialects
• Quest Toad for SQL Server: Probably the reference third-party DB management tool; trialware.
• Apex SQL Refactor: Another trialware code completion / refactoring/reformatting add-in for SSMS, this one claims to keep formatting for free after the trial runs out
• Tidycode T-Sql Formatter: Command-line trialware formatter
  

Here are features that I would be looking for / comparing:

• Open-source / libre-ness
• Free-ness (as in beer)
• Installable-ness (avoiding online-only / web service solutions)
• Accessibility / easy testing (looking for online / form-based solutions)
• Batchable-ness / command-line execution (for mass-reformatting)
• SSMS plugin availability
• Cross-platform support (if not online-only of course)
• Access to a parse tree (and completeness/detail of the parse tree)
• Formatting according to my personal preferences
• Ability to nicely format complete T-SQL scripts (eg stored procedures), not just individual queries
• Input and output filters (to take and spit out code, eg VBScript, for ad-hoc SQL queries)
• Support for multiple SQL Dialects
• Support for different SQL formatting preferences
• Recent Activity / Updates
• Completeness, in terms of language/syntax coverage
• Completeness, in terms of T-SQL parser "edge cases": strange decimal/money parsing behaviour, nested comments, etc.
  

Your Formatting preferences? Who are you?

The only reason my personal preferences are important here, is that I'm the one writing this (and, as far as I can tell, the only one using it too :) ).

What I can do, however, is explain the rationale behind my preferences, in the hope that I might sway someone's opinion:

• I find that too much whitespace in the body/joins distracts from the structure of the query, especially if you end up having to scroll to find parts of the query. This is why I'm not fond of indenting the "ON" portion of a join clause
• I find that logical expressions are easiest to read (and write) when each portion is on its own line. This applies regardless of whether it's in a join clause's "ON" conditions, or the "WHERE" clause
• I find it very important to be able to write SQL (in a variety of editors) in the target format, without needing something to clean up after you. This is the main reason I don't like "Aligned" SQL formatting. I understand it can be more legible, but it's too much of a pain to maintain (esp. in embedded/ad-hoc SQL queries). It also breaks when you use tabs (in different editors with different tab stops), and I like tabs! They're easy-to-navigate whitespace!
  

What if I want my SQL formatted differently?

I am completely open to providing additional formatting options, obviously within the time I have available to devote to this project. As it's open source and hosted on github, it's also trivial to fork the project, download to your local machine and get cracking on any changes you'd like to see!

If you don't want to, or can't make the changes yourself and you can't get a hold of me or I don't have time to work on the changes, there is always the host of commercial applications identified above!