SqlParameterAttribute Class

.NET Standard 2.x

Defines a parameter with name and type in the model class.

Namespace: SnapObjects.Data

Assembly: SnapObjects.Data.dll

Inheritance Constructor

System.Attribute

SnapObjects.Data.ISqlParameter

Syntax

   [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, AllowMultiple = true)]
   public class SqlParameterAttribute : Attribute, ISqlParameter

Constructors

Name	Description
SqlParameterAttribute(string name, Type dataType)	Initializes a new instance of the SqlParameterAttribute class.

Properties

Name	Return Type	Description
DataType	Type	Gets the data type of the parameter.
Direction	System.Data.ParameterDirection	Gets the direction type of the parameter.
Name	string	Gets the name of the parameter.

Remarks

The parameter can be referenced by its name in the SQL expression parameter for the other attributes in the model class. The format to make reference: :paramName.

Examples

The following code example demonstrates how to use the SqlParameter attribute. It applies the SqlParameter attribute named "nameArgument" to the DepartmentByName class. Then you can use ":nameArgument" in any raw SQL expression parameter for the other attributes applied to the DepartmentByName class.

Model: DepartmentByName

using System;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using SnapObjects.Data;

namespace Appeon.ApiDoc.Models.School
{
    /// <summary>
    /// This model class maps to the dbo.Department table.
    /// It uses the primary key to generate the Where clause for the Update operation.
    /// The SqlParameter attribute defines an argument: nameArgument.
    /// The SqlWhere attribute adds a Where clause using the nameArgument argument.
    /// 
    /// DepartmentID is the primary key.
    /// </summary>
    [SqlParameter("nameArgument", typeof(string))]
    [Table("Department", Schema = "dbo")]
    [UpdateWhereStrategy(UpdateWhereStrategy.KeyColumns)]
    [SqlWhere("Name = :nameArgument")]
    public class DepartmentByName
    {
        [Key]
        public int DepartmentID { get; set; }

        public string Name { get; set; }

        public decimal Budget { get; set; }

        public DateTime StartDate { get; set; }

        public int? Administrator { get; set; }

    }
}

Example Method:

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

namespace Appeon.ApiDoc.SqlParameterAttributeExamples
{
    public class SqlParameterAttributeExample
    {
        private SchoolContext _context;

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

        public void Example()
        {
            // Gets the SQL statement.
            string sql =ModelSqlBuilder.GetBuilder<DepartmentByName>(_context).QuerySql;

            Console.WriteLine("SQL statement:");
            Console.WriteLine(sql);

            // Executes the SQL statement to query the English department.
            var department = _context.SqlExecutor.Select<DepartmentByName>(sql, "English");

            /* This code example produces the following output:
            
            SQL statement:
            SELECT
             [DepartmentID],
            [Name],
            [Budget],
            [StartDate],
            [Administrator]
            FROM [dbo].[Department]
            WHERE ([Name] = @nameArgument)
            */

            /* Internally generated T-SQL:
            
            exec sp_executesql N'SELECT
             [DepartmentID],
            [Name],
            [Budget],
            [StartDate],
            [Administrator] 
            FROM [dbo].[Department] 
            WHERE ([Name] = @nameArgument)',N'@nameArgument nvarchar(4000)',@nameArgument=N'English'
            */
        }
    }
}

Applies to

.NET Standard

2.x