| Re: [stellation-res] MySql Port |
Jonathan: Looks terrific. I haven't integrated into my workspace yet, because it's in the middle of a boatload of incomplete changes. I've done an eyeball check of your changes to AbstractDatabase, BasicDatabase, and MySQLDatabase. It looks really good. I'm going to be spending most of today building a swingset for my daughter, so I won't have much hacking time today. But getting this integrated is moving up to the top of my priority queue. This is a very impressive piece of work! -Mark On Sun, 2002-09-29 at 13:44, Jonathan Gossage wrote: > I have finally got the coding and testing portion of the MySql port > completed. I apologize for the time it took but I was also involved in the > final phase of a product release cycle at work. Testing has only been done > on Windows XP using MySql and Postgres as databases. > > The central problem in providing support for MySql within Stellation is that > MySql does not support the implicit generation of indexes when handling > foreign key constraints, unlike other databases. Such indexes may be needed > in both the source (child) and referenced (parent) tables. Thus we are faced > with the problem of dealing with cross-table relationships when generating > the database schema. > > We are also faced with the problem of adding tables to the database after > the initial tables have been generated. Currently, this problem arises when > adding the tables for the various artifacts. We need to be able to handle > the possible need for additional indexes to be created in existing tables. > > I took the following approach in building a solution for this problem. > > 1. I decoupled the generation of the abstract tables describing the > Stellation database from the process of actually creating the tables in the > database. The set of tables is now accumulated in a collection stored in > BasicDatabase. This has the additional long-term advantage of making a > programmatically accessible version of the schema available to any component > that may need it. > > 2. I created additional nested classes within the Table class to allow the > recording of cross table relationships. This bookeeping is needed to support > the correct generation of indexes in tables that are created before other > tables that reference them. > > 3. I extended the BasicDatabase.createTable method to recognize when it may > be necessary to generate the additional indexes required by MySql and to do > so at the appropriate time. > > 4. I extended the BasicDatabase.createTable method to recognize when > additional indexes might be required for already existing tables and to > generate the additional indexes for those tables. > > In addition a few smaller problems also had to be dealt with. > 1. MySql treats BLOBS as case sensitive character data. If you want to store > binary data in a BLOB you must escape certain characters. This has been > implemented. > > 2. MySql specific data format requirements have been addressed. > > I looked at one related area at the same time. All the databases except > Postgres have JDBC drivers that support/require TCP/IP connections. > Accordingly, I defined an extended format for the location option that is > supported by all database types. The general form of the location option is > now > > database type:[database name]:[hostname]:[port]:[database user]:[database > user password] > > The following defaults are provided: > database name - Stellation > hostname - localhost > port - database specific > database user - stellation > database user password - ignored > > Trailing fields can be omitted. You can also omit the content of a > positional field by coding consecutive ::. > > I have not yet addressed the documentation requirements since I believe that > significant restructuring is needed to accomodate both database specific and > platform specific sections. > > Modified files are attached. I hope thay are all there as I do not know how > to easily determine which files I have modified. > > Regards > > Jonathan Gossage > > Personal Email > jgossage@xxxxxxxx > > Business Email jonathan@xxxxxxxxxxxxxx -- Mark Craig Chu-Carroll, IBM T.J. Watson Research Center *** The Stellation project: Advanced SCM for Collaboration *** http://www.eclipse.org/stellation *** Work Email: mcc@xxxxxxxxxxxxxx ------- Personal Email: markcc@xxxxxxxxxxx
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