ISqlModelMapper.TrackDeleteRange<TModel>(IEnumerable<TModel> models) Method

.NET Standard 2.x

Tracks one or more database table delete operations. The data that will be deleted from the database table is cached in the TModel object. When ISqlModelMapper.SaveChanges method is called, one or more SQL DELETE statements will be first generated using the data cached in the TModel object and the mapping information defined in TModel class, and then executed.

Namespace: SnapObjects.Data

Assembly: SnapObjects.Data.dll

Syntax

  public ISqlModelMapper TrackDeleteRange<TModel>(IEnumerable<TModel> models);

Type Parameters

TModel

The type of a model class.

Parameters

models System.Collections.Generic.IEnumerable<TModel>

A collection of TModel type used for deleting one or multiple records.

Returns

SnapObjects.Data.ISqlModelMapper

Returns an ISqlModelMapper object, which can be used for executing other methods.

Examples

The following code example demonstrates how to delete a list of students.

using Appeon.ApiDoc.Models.School;
using System;
using System.Collections.Generic;

namespace Appeon.ApiDoc.ISqlModelMapperExamples
{
    public class TrackDeleteRangeExample
    {
        private SchoolContext _context;

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

        public void Example()
        {
            var mapper = _context.SqlModelMapper;

            // Creates two new students.
            var newStudentA = new Person()
            {
                LastName = "Ruskin",
                FirstName = "Lionel",
                EnrollmentDate = new DateTime(2019, 1, 1),
                Discriminator = "Student"
            };

            var newStudentB = new Person()
            {
                LastName = "Effie",
                FirstName = "Lilith",
                EnrollmentDate = new DateTime(2019, 1, 1),
                Discriminator = "Student"
            };

            var students = new List<Person>() { newStudentA, newStudentB };

            // Tracks the new students and saves changes to the database.
            var dbResult = mapper.TrackCreateRange(students)
                                 .SaveChanges();

            Console.WriteLine("{0} records have been inserted into the database.",
                dbResult.InsertedCount);

            // Deletes these students from the database.
            dbResult = mapper.TrackDeleteRange(students).SaveChanges();

            Console.WriteLine("{0} records have been deleted from the database.",
                dbResult.DeletedCount);

            /* The code produces the following output:
            
            2 records have been inserted into the database.
            2 records have been deleted from the database.
            */
        }
    }
}

Example Refer To

Model Class: Person

Applies to

.NET Standard

2.x