自定义数据库方言

public class MySQL5DialectNoFK extends MySQL5InnoDBDialect {
	@Override
	public String getTableTypeString() {

		return "ENGINE=InnoDB DEFAULT CHARSET=utf8";
	}

	public MySQL5DialectNoFK() {
		super();
		registerFunction("order_china", new SQLFunctionTemplate(
				new StringType(), "convert(?1 using ?2)"));

	}

	@Override
	public String getAddForeignKeyConstraintString(String constraintName, String[] foreignKey, String referencedTable,
			String[] primaryKey, boolean referencesPrimaryKey) {
		String sql = "";
		for(String key : foreignKey) {
			sql += "alter table" + referencedTable + " drop foreign key " + key + ";";
		}
		return sql;
	}
}