Files to look at:

• Program.cs (VB: Program.vb)

XPO - How to Use the Database Schema Migrations API

How It Works

To support Database Schema Migrations, XPO data store providers implement the following interfaces:

• IDataStoreSchemaMigrationProvider - exposes methods used to compare the Data Model with the database schema and to apply differences to the database schema.
• IUpdateSchemaSqlFormatter - exposes methods used to generate SQL statements for a manual schema update.

To retrieve differences and generate the schema migration script programmatically, cast a data store provider object to these interfaces and call the IDataStoreSchemaMigrationProvider.CompareSchema and IUpdateSchemaSqlFormatter.FormatUpdateSchemaScript methods subsequently.

The FormatUpdateSchemaScript method returns SQL statements as a plain text. If you want to get SQL statements as an array, use the IUpdateSchemaSqlFormatter.FormatUpdateSchemaStatements method.

Code Examples:

C#

IDataStore provider = XpoDefault.GetConnectionProvider(ConnectionString, AutoCreateOption.DatabaseAndSchema);
var migrationProvider = (IDataStoreSchemaMigrationProvider)provider;
var migrationScriptFormatter = (IUpdateSchemaSqlFormatter)provider;

var dictionary = new ReflectionDictionary();
DBTable[] targetSchema = dictionary.GetDataStoreSchema(typeof(Customer), typeof(Order), typeof(Product));

var migrationOptions = new SchemaMigrationOptions();
var updateSchemaStatements = migrationProvider.CompareSchema(targetSchema, migrationOptions);
string sql = migrationScriptFormatter.FormatUpdateSchemaScript(updateSchemaStatements);

VB.NET

Dim provider As IDataStore = XpoDefault.GetConnectionProvider(ConnectionString, AutoCreateOption.DatabaseAndSchema)
Dim migrationProvider = DirectCast(provider, IDataStoreSchemaMigrationProvider)
Dim migrationScriptFormatter = DirectCast(provider, IUpdateSchemaSqlFormatter)

Dim dictionary = New ReflectionDictionary()
Dim targetSchema() As DBTable = dictionary.GetDataStoreSchema(GetType(Customer), GetType(Order), GetType(Product))

Dim migrationOptions = New SchemaMigrationOptions()
Dim updateSchemaStatements = migrationProvider.CompareSchema(targetSchema, migrationOptions)
Dim sql As String = migrationScriptFormatter.FormatUpdateSchemaScript(updateSchemaStatements)

## Does this example address your development requirements/objectives?

(you will be redirected to DevExpress.com to submit your response)