SqlColumnAttribute Class

.NET Standard 2.x

Represents the database column that a property is mapped to.

Namespace: SnapObjects.Data

Assembly: SnapObjects.Data.dll

Inheritance Constructor

System.Attribute

Syntax

   [AttributeUsage(AttributeTargets.Property)]
   public class SqlColumnAttribute : Attribute, ISqlColumn

Constructors

Name	Description
SqlColumnAttribute(string column)	Initializes a new instance of the SqlColumnAttribute class.
SqlColumnAttribute(string tableAlias, string column)	Initializes a new instance of the SqlColumnAttribute class.
SqlColumnAttribute(string tableAlias, string column, string columnAlias)	Initializes a new instance of the SqlColumnAttribute class.

Properties

Name	Return Type	Description
Column	string	Gets the name of the column the property is mapped to.
ColumnAlias	string	Gets the alias of the column the property is mapped to.
ColumnAliasDefined	bool	Gets whether the column has an alias.
Order	int	Gets or sets the zero-based order of the column the property is mapped to.
TableAlias	string	Gets the alias of the table where the column belongs to.
TableAliasDefined	bool	Gets whether the table (where the column belongs to) has an alias.
TypeName	string	Gets or sets the data type (specific to the database provider) of the column the property is mapped to.

Remarks

Compared to the System.ComponentModel.DataAnnotations.Schema.ColumnAttribute class provided by .NET, the only difference is we support the column alias and the table alias.

If there is only one table in the model class that needs to be mapped, and the property name of the model class is the same as the column name of the database table (case is insensitive), then the SqlColumn attribute can be ignored.

Examples

Example 1

The following code example demonstrates how to use the constructor: SqlColumn (columnname). When a property in the model is applied with SqlColumn (columnname), it indicates the property is mapped to that table column.

Model: DepartmentSqlColumn

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

namespace Appeon.ApiDoc.Models.School
{
    [FromTable("Department", Schema = "dbo")]
    public class DepartmentSqlColumn
    {
        [Key]
        public int DepartmentID { get; set; }

        [SqlColumn("Name")]
        public string DepartmentName { get; set; }

        public decimal Budget { get; set; }

        public DateTime StartDate { get; set; }

        public int? Administrator { get; set; }
       
    }
}

Example Method: Example1

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

namespace Appeon.ApiDoc.SqlColumnAttributeExamples
{
    public class SqlColumnAttributeExample
    {
        private SchoolContext _context;

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

        public void Example1()
        {
            // Gets the SQL statement.
            string sql = ModelSqlBuilder.GetBuilder<DepartmentSqlColumn>(_context).QuerySql;

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

            // Executes the SQL statement.
            var departments = _context.SqlExecutor.Select<DepartmentSqlColumn>(sql);

            /* The code produces the following output:
            
            SQL statement:
            SELECT
             [DepartmentID],
            [Name],
            [Budget],
            [StartDate],
            [Administrator]
            FROM [dbo].[Department]
            */
        }
    }
}

Example 2

The following code example demonstrates how to use the constructor: SqlColumn (tableAlias, columnname). When a property in the model is applied with SqlColumn (tableAlias, columnname), it indicates the property is mapped to the specified column in the specified table. tableAlias is defined in Table or FromTable.

Model: DepartmentSqlColumn2

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

namespace Appeon.ApiDoc.Models.School
{
    [FromTable("depart", "Department", Schema = "dbo")]
    public class DepartmentSqlColumn2
    {
        [Key]
        public int DepartmentID { get; set; }

        [SqlColumn("depart", "Name")]
        public string DepartmentName { get; set; }

        public decimal Budget { get; set; }

        public DateTime StartDate { get; set; }

        public int? Administrator { get; set; }

    }
}

Example Method: Example2

        public void Example2()
        {

            // Gets the SQL statement.
            string sql = ModelSqlBuilder.GetBuilder<DepartmentSqlColumn2>(_context).QuerySql;

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

            // Executes the SQL statement.
            var departments = _context.SqlExecutor.Select<DepartmentSqlColumn2>(sql);

            /* The code produces the following output:
            
            SQL statement:
            SELECT
             [DepartmentID],
            [depart].[Name],
            [Budget],
            [StartDate],
            [Administrator]
            FROM [dbo].[Department] AS [depart]
            */
        }

Example 3

The following code example demonstrates how to use the constructor: SqlColumn (tableAlias, columnname, columnAlias). When a property in the model is applied with SqlColumn (tableAlias, columnname, columnAlias), it indicates the property is mapped to the specified column in the specified table. columnAlias is the alias name of column.

Model: DepartmentSqlColumn3

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

namespace Appeon.ApiDoc.Models.School
{
    [FromTable("depart", "Department", Schema = "dbo")]
    public class DepartmentSqlColumn3
    {
        [Key]
        public int DepartmentID { get; set; }

        [SqlColumn("depart", "Name", "DepartName")]
        public string DepartName { get; set; }

        public string Name { get; set; }

        public decimal Budget { get; set; }

        public DateTime StartDate { get; set; }

        public int? Administrator { get; set; }

    }
}

Example Method: Example3

        public void Example3()
        {
            // Gets the SQL statement.
            string sql = ModelSqlBuilder.GetBuilder<DepartmentSqlColumn3>(_context).QuerySql;

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

            // Executes the SQL statement.
            var departments = _context.SqlExecutor.Select<DepartmentSqlColumn3>(sql);

            /* The code produces the following output:
            SQL statement:
            SELECT
             [DepartmentID],
            [depart].[Name],
            [Name],
            [Budget],
            [StartDate],
            [Administrator]
            FROM [dbo].[Department] AS [depart]
            */
        }

Applies to

.NET Standard

2.x