examples/org.eclipse.epsilon.examples.oo2dbsync/oo2dbsync.epl

// Class and table with the same name in the two models
pattern ClassAndTable 
	class : OO!Class,
	table : DB!Table guard: class.name = table.name {
	
	onmatch {
		// Synchronise table columns with class attributes
		for (attr in class.attributes) {
			var col = table.columns.selectOne(col|col.name=attr.name);
			if (not col.isDefined()) {
				col = new DB!Column;
				table.columns.add(col);
			}
			sync(attr, col);
		}
	}
	
}

// Class without corresponding table
pattern ClassAndNoTable
	class : OO!Class,
	no table : DB!Table from: DB!Table.all.select(table|table.name = class.name) {
	
	onmatch {
		// Create a table with that name
		var table : new DB!Table;
		DB!Database.all.first().tables.add(table);
		table.name = class.name;
		for (attr in class.attributes) {
			var col = new DB!Column;
			table.columns.add(col);
			sync(attr, col);
		}
	}
}

// Table without corresponding class
pattern TableAndNoClass
	table : DB!Table,
	no class : OO!Class from: OO!Class.all.select(class|class.name = table.name) {
	
	onmatch {
		// Delete the table
		delete table;
	}
}

operation sync(attr : OO!Attribute, col : DB!Column) {
	col.name = attr.name;
	col.type = attr.type.toDbType();
}

operation String toDbType() {
	if (self = "String") return "nvarchar";
	else return "int";
}