the Use of business servers and restrictions to verify the uniqueness of objects

If there is a need to verify the uniqueness of data entered, it is necessary in the method OnUpdate business server to generate read data and compare the data from the database with the entered data.

Be aware that the object can be either just created or already be in the database. If the object is already in the database, he will get the list reads the data and there is a conflict.

Example

You want to check the uniqueness of the entered credit card number.

• Add business server КредитнаяКартаБС and put the object КредитнаяКарта link to the business server.
• The method OnUpdate should subtract all Creditcart client and check if there are any cards with that number.

Code using LinqProvider:

var ds = (SQLDataService)DataServiceProvider.DataService;
var кредитныеКарты = ds.Query<КредитнаяКарта>(КредитнаяКарта.Views.КредитнаяКартаE)
                     .Count(k => k.Клиент.__PrimaryKey == UpdatedObject.Клиент.__PrimaryKey 
                              && k.Номер == UpdatedObject.Номер);

Thus, in the variable кредитныеКарты is the amount of the desired credit cards. If these cards are already there, this number will be unequal to zero. However, if Карта not created and updated, it will return unit, as our database is information about the updated credit card.

We should Refine the condition by adding a comparison with the current map, using LinqProvider:

var ds = (SQLDataService)DataServiceProvider.DataService;
var кредитныеКарты = ds.Query<КредитнаяКарта>(КредитнаяКарта.Views.КредитнаяКартаE)
                     .Count(k => k.Клиент.__PrimaryKey == UpdatedObject.Клиент.__PrimaryKey 
                              && k.Номер == UpdatedObject.Номер
                              && k.__primaryKey != UpdatedObject.__PrimaryKey);

Thus, it verifies the uniqueness of the numbers generated Кредитной карты.