| [stellation-res] MySql Port |
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
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AbstractDatabase.java
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AbstractDBAccessPoint.java
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BasicDatabase.java
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DB2Database.java
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FirebirdDatabase.java
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MysqlDatabase.java
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OracleDatabase.java
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PostgresDatabase.java
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RepositoryDefinition.java
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Table.java
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TableIterator.java
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TestTable.java
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ArtifactAgent.java
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CompoundArtifactAgent.java
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DataArtifact.java
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DataArtifactAgent.java
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TextArtifactAgent.java
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