DwSelectAttribute Class

.NET Standard 2.x

Specifies the query statement.

Namespace: DWNet.Data

Assembly: DWNet.Data.dll

Inheritance Constructor

System.Attribute

Syntax

    [AttributeUsage(AttributeTargets.Class, AllowMultiple = false)]
    public class DwSelectAttribute : Attribute

Constructors

Name	Description
DwSelectAttribute(string select)	Initializes a new instance of the DwSelectAttribute class.

Properties

Name	Return Type	Description
Select	string	The query statement.

Remarks

Corresponding to the DataWindow query statement.

If the query statement is a PBSelect, use @(_COLUMNS_PLACEHOLDER_) to replace the column definition, for easier maintenance of columns.

Examples

The following code example demonstrates how to use the Model DwSelect attribute. The DwSelect attribute uses the PBSELECT syntax which will be used to generate standard SQL statement when retrieving data.

Model: D_Person

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using SnapObjects.Data;
using DWNet.Data;
using Newtonsoft.Json;

namespace Appeon.ApiDoc.Models
{
    [DataWindow("d_person", DwStyle.Grid)]
    [Table("Person", Schema = "dbo")]
    #region DwSelectAttribute  
    [DwSelect("PBSELECT( VERSION(400) TABLE(NAME=\"Person\" ) @(_COLUMNS_PLACEHOLDER_) )")]
    #endregion
    [UpdateWhereStrategy(UpdateWhereStrategy.KeyAndConcurrencyCheckColumns)]
    [DwKeyModificationStrategy(UpdateSqlStrategy.DeleteThenInsert)]
    public class D_Person
    {
        [Key]
        [Identity]
        [DwColumn("Person", "PersonID")]
        public int Personid { get; set; }

        [ConcurrencyCheck]
        [DwColumn("Person", "LastName")]
        public string Lastname { get; set; }

        [ConcurrencyCheck]
        [DwColumn("Person", "FirstName")]
        public string Firstname { get; set; }

        [ConcurrencyCheck]
        [DwColumn("Person", "HireDate")]
        public DateTime? Hiredate { get; set; }

        [ConcurrencyCheck]
        [DwColumn("Person", "EnrollmentDate")]
        public DateTime? Enrollmentdate { get; set; }

        [ConcurrencyCheck]
        [DwColumn("Person", "Discriminator")]
        public string Discriminator { get; set; }

    }

}

Example Method:

using System;
using DWNet.Data;

namespace Appeon.ApiDoc.DwSelectAttributeExamples
{
    public class DwSelectAttributeExample
    {
        private readonly SchoolContext _context;

        public DwSelectAttributeExample(SchoolContext dataContext)
        {
            // Sets the data context.
            _context = dataContext;
        }

        public void Example()
        {
            var datastore = new DataStore("d_person", _context);
            datastore.Retrieve();

            /* The following SQL is generated:
            
            SELECT
             [Person].[PersonID],
            [Person].[LastName],
            [Person].[FirstName],
            [Person].[HireDate],
            [Person].[EnrollmentDate],
            [Person].[Discriminator] 
            FROM [Person]
            */
        }
    }
}

Example Refer To

DataWindow File: d_person