ISqlModelMapper.Scalar<TModel, TValue>(string expression, params object[] parameters) Method

.NET Standard 2.x

Retrieves data from the first column, in the first row, for the specified SQL expression, according to the criteria specified in a TModel class.

Namespace: SnapObjects.Data

Assembly: SnapObjects.Data.dll

Syntax

  public TValue Scalar<TModel, TValue>(string expression, params object[] parameters);

Type Parameters

TModel

The type of a model class.

TValue

The type of the value retrieved.

Parameters

expression System.String

A SQL expression string used to get data from the first column in the first row.

parameters System.Object[]

(Optional) One or more values that you want to use as retrieval arguments in the SQL SELECT statement defined in TModel.

Returns

TValue

Returns the data from the first column in the first row, of the retrieved data. Its data type is determined by the return value of the SQL expression.

Remarks

At least one data row must be retrieved according to the specified criteria, otherwise exceptions will be thrown.

Examples

The following code example demonstrates how to calculate the minimum budget for departments. The Scalar method retrieves data of the first column in the first row for the SQL expression min(Budget).

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

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

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

        public void Example()
        {
            // Calculates the minimum budget for departments.
            decimal MinBudget = _context.SqlModelMapper
                                        .Scalar<Department, decimal>("min(Budget)");

            Console.WriteLine("The minimum budget is {0}.",
                MinBudget.ToString("N0"));

            /* The code produces the following output:
            
            The minimum budget is 120,000.
            */
        }
    }
}

Example Refer To

Model Class: Department

Applies to

.NET Standard

2.x