Database Change Script
Once you already have a database populated with data you will typically want to apply changes to the database by running an update script against your database to preserve your data.
This generator helps you build such a script based on your changes to the Xomega object model. The script will be rerunnable, meaning that it will check if the necessary changes have already been made in the database before making a change.
Generator inputs
The generator uses the structure of the target database and the current state of the Xomega model to generate a DDL update script that will bring the database in sync with the model.
If certain database tables have been specifically excluded from the object model, you need to make sure that they are excluded in the database connection configuration as well. Otherwise, the generator will assume that they have been deleted from the model and will add statements to drop those tables into the script.
Generator outputs
This generator creates a rerunnable DDL script that makes updates to the target database to synchronize it with the current model.
This is similar to using standard Entity Framework migration tools.
Configuration
The following sections describe the configuration parameters used by the generator.
Generator parameters
The following table lists configuration parameters that are set as the generator’s properties.
| Parameter | Value Example | Description |
|---|---|---|
| Generator Name | Database Change Script | The name of the current configuration of the generator that will appear in the model project and the build output. |
| Folder Name | Data Layer | Folder path to the generator inside the Model project. The folders are separated by a backslash (\). |
| Include In Build | False | A flag indicating whether or not running this generator should be included in building of the model project. |
| Output | ||
| Output Path | ../database/db_update.sql | Relative path where to output generated DDL update script. |
| Database | ||
| Connection String | Use Project Setting | Database connection string for the target database. Edited via the standard VS Connection Properties dialog, which also sets the other Database parameters of the generator, and allows saving it for the entire project. Value 'Use Project Setting' takes this value from the corresponding property of the model project. |
| Data Provider | .NET Framework Data Provider for SQL Server | Name of the data provider selected for the connection string. Value 'Use Project Setting' takes this value from the corresponding property of the model project. Option Reset Connection Info allows resetting the connection string. |
| Database | SQL Server | Database type of the source database. Value 'Use Project Setting' takes this value from the corresponding property of the model project. |
| Database Case | PascalCase | The database case for the database objects' names: PascalCase, lower_snake or UPPER_SNAKE. Value 'Use Project Setting' takes this value from the corresponding property of the model project. |
| Database Version | 16.0 | The version of the source database. Value 'Use Project Setting' takes this value from the corresponding property of the model project. |
| Parameters | ||
| Rerunnable | True | Specifies whether to make the generated SQL script rerunnable. Default is False. |
Model configuration
The generator doesn't use any other global configurations in the model.
Common configurations
The generator configuration allows you to specify a database connection string for the database that you need to update. You can either use the project's default settings or provide a specific database.
Sometimes you may want to connect to different databases, e.g. to generate incremental changes for the bleeding edge development database, and then, closer to the release, generate an update script for a more stable testing database.
How to use the generator
The sections below provide some details on how to work with the generator.
Running the generator
You can run this generator for the entire model only. For that, you need to select it in the model project, and then select Generate menu from either the context menu or the top-level Project menu.
You can rerun the generator when you change any objects, fields, or types in the model, which may require re-running other generators that depend on the same model elements, such as the generator of Service Implementations.
You don't need to include this generator in the model build process. Normally, you need to run it only when you are ready to apply your model change to your database, but you can also run it as a diff tool to check if any of your model changes affected the database structure.
Customizing the output
You should always carefully review the generated script before running it, to make sure it doesn't cause any negative side effects.
If, upon review, you determine that the generated script needs to be updated, you should make your updates in a copy of the script to preserve your changes. Any additional scripts that need to be run for the migration must be in separate files.
Cleaning the generator’s output
The generator doesn't support cleaning the generated output.
Once you run the update DDL script against your database, a subsequent run of this generator should produce an empty update script, which would indicate that the target database is in sync with the model.