IQueryWhereBuilder.WhereIsNotNull(string left) Method

.NET Standard 2.x

Creates a WHERE clause, and adds a search condition to the WHERE clause. Uses IS NOT NULL operator to search for values that are not null.

Namespace: SnapObjects.Data

Assembly: SnapObjects.Data.dll

Syntax

  IQueryAndOrBuilder<TModel> WhereIsNotNull(string left);

Parameters

left System.String

A SQL expression on the left of the IS NOT NULL operator.

Returns

IQueryAndOrBuilder<TModel>

Returns an IQueryAndOrBuilder<TModel> object which can be used to add more search conditions to the current WHERE clause.

Examples

The following code example uses the WhereIsNotNull method to specify that data retrieved from the "Person" table must have a not null value for EnrollmentDate.

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

namespace Appeon.ApiDoc.IQueryWhereBuilderExamples
{
    public class WhereIsNotNullExample
    {
        private SchoolContext _context;
        
        public WhereIsNotNullExample(SchoolContext dataContext)
        {
            // Sets Data Context
            _context = dataContext;
        }

        public async Task<int> Example() 
        {
            // Get a QueryBuilder.
            var Builder = _context.SqlModelMapper.GetQueryBuilder<Person>();
            
            // Defines a WHERE condition that the column of EnrollmentDate is not empty.
            Builder.WhereIsNotNull("EnrollmentDate");
            
            var result = (await Builder.LoadAsync()).FirstOrDefault();
            
            if (result != null) 
            {
                Console.WriteLine("PersonID:    {0}", result.PersonID);
                Console.WriteLine("FirstName:   {0}", result.FirstName);
                Console.WriteLine("LastName:    {0}", result.LastName);
                Console.WriteLine("HireDate:    {0}", result.HireDate);
                Console.WriteLine("EnrollmentDate:  {0}", result.EnrollmentDate);
                Console.WriteLine("Discriminator:   {0}", result.Discriminator);
                
                return result.PersonID;
            }
            else 
            {
                Console.WriteLine("Not found!");
                
                return 0;
            }
            
            /*This code example produces the following output:   
            
                PersonID:    2
                FirstName:   Gytis
                LastName:    Barzdukas
                HireDate:
                EnrollmentDate:  9/1/2005 12:00:00 AM
                Discriminator:   Student
            */
        }
    }
}

Example Refer To

Model Class: Person

Applies to

.NET Standard

2.x