What is it?

Pure.Migration is an engine to generate empty *.sql scripts which will be executed in correct order on selected database. It is a set of powershell cmd-lets applied to Nuget Package Manager Console in Visual Studio which makes database schema maintanance a lot easier. It is based on EntityFramework solution and is written entirely in Powershell.

Features

• Generates following files which are automatically added to selected .NET project:
• empty *.sql script where you put DDL commands
• empty *.sql revert script where you can put DDL commands which will be executed during database downgrade
• data import script (generated on demand)
• Adds following commnads to the Package Manager Console:
• new-migration to generate new set of scripts
• migrate-database to update database schema
• revert-database to downgrade database schema
• Multidatabase support (ADO-based access) for:
• Sql Server
• MySql
• Offers great performance
• Guarantees scripts execution in correct order when you use source code repository like Git, SVN or TFS
• Provides simple problems detection when some script is missing or database versioning is broken

Installation

The engine is published as NuGet packages.

To install SqlServer driver use command: install-package Pure.Migrations.SqlServer

To install MySql driver use command: install-package Pure.Migrations.MySql

Each driver depends on Pure.Migrations.Core package which will be installed automatically.

Commands

Create new migration

new-migration -name <string> -project <string> [-migrationsDir <string>] [-force] [-withData]

Option	Description
-name <string>	Specifies the name of the custom script.
-project <string>	Specifies the Visual Studio project where the scripts will be created.
-migrationsDir <string>	Specifies the name of the directory in the selected project that contains all migration scripts. If ommited, the directory will be named "Migrations".
-force	Overwrites all custom scripts with provided name.
-withData	Generates separate script for data import (seed script).

Update database schema to target version

migrate-database -project <string> [-migrationsDir <string>] [-connectionStringName <string>] [-targetMigration <string>] [-detailed]

Option	Description
-project <string>	Specifies the Visual Studio project where the migration scripts are located.
-migrationsDir <string>	Specifies the name of the directory in the selected project that contains all migration scripts. If ommited, the directory will be named "Migrations".
-connectionStringName <string>	Specifies the name of a connection string to use from the application’s configuration file located in a Visual Studio project which is set as startup project.
-targetMigration <string>	Specifies the name of a particular script to update the database to. If ommited, all scripts will be executed.
-detailed	Writes detailed (verbose) information about command execution to the console.

Revert database schema to target version

revert-database -project <string> [-migrationsDir <string>] [-connectionStringName <string>] [-targetMigration <string>] [-detailed]

Option	Description
-project <string>	Specifies the Visual Studio project where the migration scripts are located.
-migrationsDir <string>	Specifies the name of the directory in the selected project that contains all migration scripts. If ommited, the directory will be named "Migrations".
-connectionStringName <string>	Specifies the name of a connection string to use from the application’s configuration file located in a Visual Studio project which is set as startup project.
-targetMigration <string>	Specifies the name of a particular script to update the database to. If ommited, all scripts will be executed.
-detailed	Writes detailed (verbose) information about command execution to the console.

Error messages explanations

The table below contains error messages with explanations which you can see while using the engine. Only not self-explanatory messages were described.

Message	Explanation
Database cannot be reverted to 'migration name' migration. Inconsistency detected between migrations and current schema version.	Occurs when SchemaVersion table in the database is corrupted or some scripts on a disk are missing (only revert-database command).
Migration 'migration name' cannot be applied because newer migration has been already applied.	Occurs when your database has newer script or scripts applied (only migrate-database command). Example: you work on a branch A and create a bunch of scripts. Then you switch to branch B, create some other scripts and apply them to the database. Next you switch back to branch A and try to apply older scripts what is not possible.
You are trying to revert database to the oldest migration which is not possible.	Occurs when you will specify first script as a -targetMigration (only revert-database command).

TODO

• Add support for Oracle database
• Add support for PostgreSql database
• Add support for MSBuild (with no need of Visual Studio)
• Add 'squash' command which will merge a set of scripts into one
• Add '-startupProject' parameter
• ...

Copyright

Copyright © 2016 Tymoteusz Kestowicz

License

Pure.Migrations is licensed under Apache v2.0.