IDetailTracker.TrackGrandDetail<TDetailModel, TGrandDetailModel>(Expression<Func<TModel, object>> propertyExpr, Expression<Func<TDetailModel, object>> detailPropertyExpr, IModelEntry<TGrandDetailModel> grandModelEntry) Method

.NET Standard 2.x

Tracks an insert, update or delete operation on the table which the granddetail model is mapped to when working with the master-detail-granddetail models where the ModelEmbedded attribute is applied in a property of the master model and a property of the detail model. The data state determines which type of operation to be performed. The data to be manipulated is cached in a TGrandDetailModel object.

When ISqlModelMapper.SaveChanges is called, a SQL statement (INSERT, UPDATE, or DELETE) will be generated using the data cached in the TGrandDetailModel object and the mapping information defined in TGrandDetailModel, and then the SQL statement will be executed.

Namespace: SnapObjects.Data

Assembly: SnapObjects.Data.dll

Syntax

  	IDetailTracker<TModel> TrackGrandDetail<TDetailModel, TGrandDetailModel>(Expression<Func<TModel, object>> propertyExpr, IModelEntry<TDetailModel> modelEntry, Expression<Func<TDetailModel, object>> detailPropertyExpr, IModelEntry<TGrandDetailModel> grandModelEntry);

Type Parameters

TDetailModel

The type of the detail model class.

TGrandDetailModel

The type of the granddetail model class.

Parameters

propertyExpr System.Linq.Expressions.Expression<Func<TModel, object>>

A property of the master model (TModel) where the ModelEmbedded attribute is applied.

The type of this property is TDetailModel.

This property is specified by an expression.

detailPropertyExpr System.Linq.Expressions.Expression<Func<TDetailModel, object>>

A property of the detail model where the ModelEmbedded attribute is applied.

The type of this property is TGrandDetailModel.

This property is specified by an expression.

grandModelEntry SnapObjects.Data.IModelEntry<TGrandDetailModel>

An IModelEntry<TGrandDetailModel> object that contains the data and data state and which will be tracked. The data corresponds to the property specified by detailPropertyExpr.

Returns

SnapObjects.Data.IDetailTracker<TModel>

Returns the current IDetailTracker<TModel> object.

Remarks

The ModelEmbedded attribute must be applied in TModel and TDetailModel to create the master-detail-granddetail relationship between TModel, TDetailModel, and TGrandDetailModel.

The ISqlModelMapper.TrackMaster method can track the master model and return the IDetailTracker<TModel> object. The IDetailTracker.TrackDetail method can be used to track the detail model. Then the IDetailTracker.TrackGrandDetail method can be used to track the granddetail model.

One-to-one-to-one

The type of the property specified by the propertyExpr parameter is TDetailModel (which represents one row in the detail database table). The type of the property specified by the detailPropertyExpr parameter is TGrandDetailModel (which represents one row in the granddetail database table). Therefore, the IDetailTracker.TrackDetailAndGrandDetail method applies to one-to-one-to-one table relationship (one master table record to one detail table record to one granddetail table record).

Examples

The following code example demonstrates how to save the master table, the detail table, and the grand-detail table synchronously; all of them have only one affected record.

using SnapObjects.Data;
using Appeon.ApiDoc.Models.School;
using System;

namespace Appeon.ApiDoc.IDetailTrackerExamples
{
    public class TrackGrandDetailExample
    {
        private readonly SchoolContext _context;

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

        public void Example(IModelEntry<DepartmentInfo> department,
                            IModelEntry<CourseInfo> course,
                            IModelEntry<CourseStudentInfo> courseStudent)
        {
            // Saves the master table, the detail table, and the grand-detail table.
            var mapper = _context.SqlModelMapper;

            var master = mapper.TrackMaster(department)
                       .TrackDetail(m => m.Courses, course)
                       .TrackGrandDetail<CourseInfo, CourseStudentInfo>(
                            m => m.Courses,
                            d => d.Students,
                            courseStudent)
                       .MasterModel;

            var dbResult = mapper.SaveChanges();

            // Shows the saving result.
            Console.WriteLine("{0} records have been inserted into the database.",
                dbResult.AffectedCount);

            /* This code example produces the following output:
            
            3 records have been inserted into the database.
            */
        }
    }
}

Example Refer To

Model Classes: CourseInfo CourseStudentInfo DepartmentInfo

Applies to

.NET Standard

2.x

See Also

IDetailTracker.TrackDetail

ISqlModelMapper.TrackMaster