Izayoi.Data.DbCommandAdapter 1.3.0

Izayoi.Data.DbCommandAdapter

This is a database operation support library that includes a fast micro O/R mapper (ORM).

Available Databases

A Database with a package that implements classes that inherit from the DbCommand and DbDataReader classes.

Applies to

Wiki

Wiki

Examples

Database

-- SQL Server Example
CREATE TABLE [dbo].[users] (
    [id]         INT           IDENTITY (1, 1) NOT NULL,
    [name]       NVARCHAR (50) NOT NULL,
    [age]        TINYINT       NOT NULL,
    [gender]     TINYINT       NOT NULL,
    [created_at] DATETIME2 (7) NOT NULL,
    [updated_at] DATETIME2 (7) NOT NULL,
    PRIMARY KEY CLUSTERED ([id] ASC)
);

CREATE TABLE [dbo].[posts] (
    [id]        INT            IDENTITY (1, 1) NOT NULL,
    [posted_at] DATETIME2 (7)  NOT NULL,
    [user_id]   INT            NOT NULL,
    [comment]   NVARCHAR (100) NOT NULL,
    PRIMARY KEY CLUSTERED ([id] ASC)
);

Map classes

using System;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

//[Table("users")]
[Table("users", Schema = "dbo")]
public class User
{
    [Key]
    [Column("id")]
    public int Id { get; set; }

    [Column("name")]
    public string Name { get; set; } = string.Empty;

    [Column("age")]
    public byte Age { get; set; }

    [Column("gender")]
    public GenderType Gender { get; set; }

    [Column("created_at")]
    public DateTime CreatedAt { get; set; }

    [Column("updated_at")]
    public DateTime UpdatedAt { get; set; }
}

//[Table("posts")]
[Table("posts", Schema = "dbo")]
public class Post
{
    [Key]
    [Column("id")]
    public int Id { get; set; }

    [Column("user_id")]
    public int UserId { get; set; }

    [Column("comment")]
    public string Comment { get; set; } = string.Empty;

    [NotMapped]
    public int IgnoreProperty { get; set; }
}

public class PostCount
{
    [Column("user_id")]
    public int UserId { get; set; }

    [Column("user_name")]
    public string UserName { get; set; } = string.Empty;

    [Column("count")]
    public int Count { get; set; }
}

• If the [Table] attribute is not defined, the class name is used as the table name.
• If the [Column] attribute is not defined, the property name is used as the column name.
• If the [NotMapped] attribute is defined, the property is excluded from the mapping.
• The [Key] attribute is set to the primary key. It is used for update or delete methods.

Data Access

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Izayoi.Data;
using Izayoi.Data.Query;
using Microsoft.Data.SqlClient;  // for SQL Server
//using Microsoft.Data.Sqlite;   // for SQLite
//using MySqlConnector;          // for MySQL
//using Npgsql;                  // for PostgreSQL

public class UserRepository
{
    private readonly string dbConnectionString;

    private readonly DbCommandAdapter dbCommandAdapter;

    private readonly DbDataMapper dbDataMapper;

    private readonly QueryOption queryOption;

    public UserRepository()
    {
        queryOption = new QueryOption(RdbKind.SqlServer);

        dbDataMapper = new DbDataMapper();

        dbCommandAdapter = new DbCommandAdapter(dbDataMapper, queryOption);

        dbConnectionString = GetDbConnectionString();
    }

    public async Task<List<User>> GetAllUserAsync(CancellationToken cancellationToken)
    {
        using SqlConnection dbConnection = new(dbConnectionString);

        using SqlCommand dbCommand = dbConnection.CreateCommand();

        dbConnection.Open();

        List<User> users;

        // Select method A (Command Text)
        {
            dbCommand.CommandText = "SELECT * FROM dbo.users";

            users = await dbCommandAdapter.ExecuteQueryAsync<User>(dbCommand, cancellationToken);
        }
        // Select method B (Query Builder)
        {
            var select = new Select()
                .SetFrom("dbo", "users", "")
                .AddField("*");

            users = await dbCommandAdapter.SelectAsync<User>(dbCommand, select, cancellationToken);
        }
        // Select method C (Auto Mapper)
        {
            users = await dbCommandAdapter.SelectAllAsync<User>(dbCommand, cancellationToken);
        }

        dbConnection.Close();

        return users;
    }

    public async Task<User?> GetUserAsync(int userId, CancellationToken cancellationToken)
    {
        // CreateConnection -> CreateCommand -> Connection.Open

        List<User> users;

        // Select method A (Command Text)
        {
            dbCommand.CommandText = "SELECT * FROM dbo.users WHERE id = @id";

            var parameter = new SqlParameter("@id", System.Data.SqlDbType.Int)
            {
                Value = userId,
            };

            dbCommand.Parameters.Add(parameter);

            users = await dbCommandAdapter.ExecuteQueryAsync<User>(dbCommand, cancellationToken);
        }
        // Select method B (Query Builder)
        {
            var select = new Select()
                .SetFrom("dbo", "users", "")
                .AddField("*")
                .AddWhere("id", "=", userId);

            // SELECT *
            // FROM dbo.users
            // WHERE id = @w_0

            users = await dbCommandAdapter.SelectAsync<User>(dbCommand, select, cancellationToken);
        }

        dbConnection.Close();

        return users.FirstOrDefault();
    }

    public async Task<User> AddUserAsync(string name, byte age, GenderType gender, CancellationToken cancellationToken)
    {
        // CreateConnection -> CreateCommand -> Connection.Open

        var user = new User()
        {
            Id = 0,
            Name = name,
            Age = age,
            Gender = gender,
            CreatedAt = DateTime.UtcNow,
            UpdatedAt = DateTime.UtcNow,
        };

        int userId = await dbCommandAdapter.InsertReturnAsync<int, User>(dbCommand, user, excludeKey: true, cancellationToken);

        user.Id = userId;

        return user;
    }

    public async Task<bool> UpdateUserAsync(User user, CancellationToken cancellationToken)
    {
        // CreateConnection -> CreateCommand -> Connection.Open

        int affectedRowCount;

        // Update method A (Auto Mapper)
        {
            user.UpdatedAt = DateTime.UtcNow;

            var excludeColumns = new string[] { "created_at" };

            affectedRowCount = await dbCommandAdapter.UpdateAsync<User>(dbCommand, user, excludeColumns, cancellationToken);
        }
        // Update method B (Query Builder)
        {
            var update = new Update()
                .SetTable("dbo","users", "")
                .AddWhere("id", "=", user.Id)
                .AddSet("name", user.Name)
                .AddSet("age", user.Age)
                .AddSet("gender", user.Gender)
                .AddSet("updated_at", DateTime.UtcNow);

            // UPDATE
            //   dbo.users
            // SET
            //   name = @s_0,
            //   age = @s_1,
            //   gender = @s_2,
            //   update_at = @s_3
            // WHERE
            //   id = @w_0

            affectedRowCount = await dbCommandAdapter.UpdateAsync(dbCommand, update, cancellationToken);
        }

        return affectedRowCount == 1;
    }

    public async Task<bool> DeleteUserAsync(User user, CancellationToken cancellationToken)
    {
        // CreateConnection -> CreateCommand -> Connection.Open

        int affectedRowCount;

        // Delete method A (Auto Mapper)
        {
            affectedRowCount = await dbCommandAdapter.DeleteAsync<User>(dbCommand, user, cancellationToken);
        }
        // Delete method B (Query Builder)
        {
            var delete = new Delete()
                .SetFrom("dbo", "users", "")
                .AddWhere("id", "=", user.Id);

            // DELETE FROM dbo.users
            // WHERE id = @w_0

            affectedRowCount = await dbCommandAdapter.DeleteAsync(dbCommand, delete, cancellationToken);
        }

        return affectedRowCount == 1;
    }

    public async Task<List<User>> GetTeenAgersAsync(CancellationToken cancellationToken)
    {
        // CreateConnection -> CreateCommand -> Connection.Open

        var select = new Select()
            .SetFrom("dbo", "users", "")
            .AddField("*")
            .AddOrder("age", OType.ASC);

        // SELECT method A (BETWEEN)
        {
            select.AddWhere("age", OpType.BETWEEN, new int[] { 13, 19 });

            // SELECT *
            // FROM dbo.users
            // WHERE age BETWEEN @w_0_0 AND @w_0_1
            // ORDER BY age ASC
        }
        // SELECT method B (IN)
        {
            select.AddWhere("age", OpType.IN, new int[] { 13, 14, 15, 16, 17, 18, 19 });

            // SELECT *
            // FROM dbo.users
            // WHERE age IN (@w_0_0, @w_0_1, @w_0_2, @w_0_3, @w_0_4, @w_0_5, @w_0_6)
            // ORDER BY age ASC
        }
        // SELECT method C (AND)
        {
            select
                .AddWhere("age", ">=", 13)
                .AddWhere("age", "<=", 19);

            // SELECT *
            // FROM dbo.users
            // WHERE age >= @w_0
            //   AND age <= @w_1
            // ORDER BY age ASC
        }
        // SELECT method D (OR)
        {
            select
                .AddWhere('(', "age", "=", 13)
                .AddWhere(CType.OR, "age", "=", 14)
                .AddWhere(CType.OR, "age", "=", 15)
                .AddWhere(CType.OR, "age", "=", 16)
                .AddWhere(CType.OR, "age", "=", 17)
                .AddWhere(CType.OR, "age", "=", 18)
                .AddWhere(CType.OR, "age", "=", 19, ')');

            // SELECT *
            // FROM dbo.users
            // WHERE (age = @w_0
            //    OR  age = @w_1
            //    OR  age = @w_2
            //    OR  age = @w_3
            //    OR  age = @w_4
            //    OR  age = @w_5
            //    OR  age = @w_6)
            // ORDER BY age ASC
        }

        List<User> users = await dbCommandAdapter.SelectAsync<User>(dbCommand, select, cancellationToken);

        return users;
    }

    public async Task<int> GetCountAsync(CancellationToken cancellationToken)
    {
        // CreateConnection -> CreateCommand -> Connection.Open

        var select = new Select()
            .SetFrom("users")
            .AddField("COUNT(*)");

        int? count = await dbCommandAdapter.ExecuteScalarAsync<int>(dbCommand, select, cancellationToken);

        return count ?? throw new Exception();
    }
}

public class PostRepository
{
    // ...

    public async Task<List<PostCount>> GetUserPostCountsAsync(CancellationToken cancellationToken)
    {
        // CreateConnection -> CreateCommand -> Connection.Open

        var select = new Select();

        select.SetFrom("dbo", "posts", "p")
            .Joins.Add(JType.LEFT_JOIN, "dbo", "users", "u", "u.id = p.user_id");

        select.Fields
            .Add("u.id", "user_id")
            .Add("u.name", "user_name")
            .Add("COUNT(u.id)", "count");

        select.Groups
            .Add("u.id")
            .Add("u.name");

        select.Orders
            .Add("count", OType.DESC);

        // SELECT
        //   u.id AS user_id,
        //   u.name AS user_name,
        //   COUNT(u.id) AS count
        // FROM dbo.posts AS p
        //   LEFT JOIN dbo.users AS u ON (u.id = p.user_id)
        // GROUP BY
        //   u.id,
        //   u.name
        // ORDER BY
        //   count DESC

        List<PostCount> postCounts = await dbCommandAdapter.SelectAsync<PostCount>(dbCommand, select, cancellationToken);

        return postCounts;
    }
}

Remarks

A DbCommandAdapter object can be reused. (Recommend)

Last updated: 24 November, 2025
Editor: Izayoi Jiichan

Copyright (C) 2024 Izayoi Jiichan. All Rights Reserved.