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1. EF DATA ANNOTATIONS HOW TO
2. EF DATA ANNOTATIONS UPDATE
3. EF DATA ANNOTATIONS MANUAL
4. EF DATA ANNOTATIONS CODE

Column captions set by this attribute can be overridden by using the GridColumn.Caption property. This attribute has no effect on columns created at design-time. Specifies the column caption for the auto-generated column. The tables below list the most common and frequently used attributes supported by the Grid Control and TreeList Control. To see a complete Data Annotation Attributes list, see this MSDN article. Alternatively, you can override the OnModelCreating method on your derived. See the Data Annotation Attributes in Data Layout Control topic to learn more. Data annotation enables you to apply attributes directly to your EF Core model.

EF DATA ANNOTATIONS MANUAL

This means that using Data Annotation Attributes allows you to completely disregard the control designer, since none of the columns require manual customization.įor the Data Layout Control, even more complex UI customization is supported - certain data attributes not only allow you to apply display formats and validation rules, but to group layout items into specific groups and tabbed containers. The grids and treelists that uses this data as their data source will recognize the attributes and automatically tweak their columns - re-arrange them, change their captions, format cell data, apply filters or validation etc.

You can define these attributes when creating your data source in code.

EF DATA ANNOTATIONS UPDATE

Note: EF does not include DatabaseGeneratedOption.Computed columns in INSERT or UPDATE statements.DevExpress data-aware controls ( GridControl, TreeList, VGridControl, PropertyGridControl and Data Layout Control) support Data Annotation Attributes provided by Microsoft.

EF DATA ANNOTATIONS CODE

The above code set the SQL Server function GETDATE() as a default value SQL which will insert the current date and time on each INSERT command. Protected override void OnModelCreating( ModelBuilder modelBuilder) Here, we will specify date function of SQL Server which will generate current date-time value on INSERT command, as shown below. However, EF does not guarantee that it will setup the actual mechanism to generate values. This tells EF that values are generated for this column in the database. In the above example, the CreatedDate property is marked with the DatabaseGeneratedOption.Computed option. CRUD Application that uses Entity Framework Core as its Data Access Layer. you must provide the unique CourseId value var maths = new Course() Using ( var context = new SchoolContext()) So, each time you will have to provide the value of the CourseId property before calling the SaveChanges() method.

EF DATA ANNOTATIONS HOW TO

In the next few tutorials, we will look at each of the above data annotations attributes and how to use them with examples.

In this tutorial, we looked at Data Annotation attributes.

Using Conventions, Using data annotation attributes, or by using fluent API. In the above example, EF will create the CourseId column in the database and will not mark it as an IDENTITY column. Entity Framework allows us various ways to configure the model class. These data annotations define rules that a separate validation stage checks against the current content of the property. This attribute is applicable to both Entity Framework & Entity Framework Core. Data annotations are attributes that add validation rules to a property or class (see ). This will be useful to override the default convention for the id properties.įor example, if you want to provide your own values to id properties instead of database generated values, use the None option, as shown below. Data Annotations Key Attribute in EF Core Leave a Comment / Novem/ 3 minutes of reading Column Attribute Complextype Attribute The Key Attribute or Primary key attribute maps the property as the primary key column in the database. The DatabaseGenerated attribute takes one out of the following three DatabaseGeneratedOption enum values:ĭatabaseGeneratedOption.None option specifies that the value of a property will not be generated by the underlying database. NET attributes which can be applied on an entity class or properties to override default conventions in EF 6 and EF Core. So, the underlying database generates a value for this column on each insert command, e.g., SQL Server creates an integer IDENTITY column with identity seed and increment to 1.ĮF 6 and EF Core provide the DatabaseGenerated data annotation attribute to configure how the value of a property will be generated. Next Data Annotations - DatabaseGenerated Attribute in EF 6 & EF CoreĪs you know, EF creates an IDENTITY column in the database for all the id (key) properties of the entity, by default.