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C#實現(xiàn)文件讀寫到SQLite數(shù)據(jù)庫

 更新時間:2025年01月08日 11:07:47   作者:碼農(nóng)君莫笑  
這篇文章主要為大家詳細介紹了使用?C#?將文件讀寫到?SQLite?數(shù)據(jù)庫的幾種方法,文中的示例代碼講解詳細,感興趣的小伙伴可以參考一下

《文件讀寫到SQLite數(shù)據(jù)庫的方法》博客中,介紹了文件讀寫到SQLite數(shù)據(jù)庫的方法,例子使用的Python語言,本文是使用 C# 將文件讀寫到 SQLite 數(shù)據(jù)庫的幾種方法的具體示例,如果有些概念模糊可參考作者以前博客。

1. 使用 BLOB 存儲文件

示例代碼:

using System;
using System.Data.SQLite;
using System.IO;
 
class Program
{
    static void Main(string[] args)
    {
        string databasePath = "example.db";
        string connectionString = $"Data Source={databasePath};Version=3;";
 
        // 創(chuàng)建數(shù)據(jù)庫和表
        using (var connection = new SQLiteConnection(connectionString))
        {
            connection.Open();
            string createTableQuery = @"
                CREATE TABLE IF NOT EXISTS Files (
                    id INTEGER PRIMARY KEY AUTOINCREMENT,
                    name TEXT NOT NULL,
                    data BLOB NOT NULL
                );";
            using (var command = new SQLiteCommand(createTableQuery, connection))
            {
                command.ExecuteNonQuery();
            }
        }
 
        // 插入文件到數(shù)據(jù)庫
        string filePath = "example.pdf"; // 替換為你的文件路徑
        InsertFile(filePath, connectionString);
 
        // 從數(shù)據(jù)庫讀取文件
        ReadFile(1, connectionString); // 假設讀取 ID 為 1 的文件
    }
 
    static void InsertFile(string filePath, string connectionString)
    {
        byte[] fileData = File.ReadAllBytes(filePath);
        string fileName = Path.GetFileName(filePath);
 
        using (var connection = new SQLiteConnection(connectionString))
        {
            connection.Open();
            string insertQuery = "INSERT INTO Files (name, data) VALUES (@name, @data)";
            using (var command = new SQLiteCommand(insertQuery, connection))
            {
                command.Parameters.AddWithValue("@name", fileName);
                command.Parameters.AddWithValue("@data", fileData);
                command.ExecuteNonQuery();
            }
        }
 
        Console.WriteLine($"File '{fileName}' has been saved to the database.");
    }
 
    static void ReadFile(int fileId, string connectionString)
    {
        using (var connection = new SQLiteConnection(connectionString))
        {
            connection.Open();
            string selectQuery = "SELECT name, data FROM Files WHERE id = @id";
            using (var command = new SQLiteCommand(selectQuery, connection))
            {
                command.Parameters.AddWithValue("@id", fileId);
                using (var reader = command.ExecuteReader())
                {
                    if (reader.Read())
                    {
                        string fileName = reader.GetString(0);
                        byte[] fileData = (byte[])reader["data"];
 
                        File.WriteAllBytes(fileName, fileData);
                        Console.WriteLine($"File '{fileName}' has been restored from the database.");
                    }
                }
            }
        }
    }
}

2. 存儲文件路徑

示例代碼:

using System;
using System.Data.SQLite;
 
class Program
{
    static void Main(string[] args)
    {
        string databasePath = "example.db";
        string connectionString = $"Data Source={databasePath};Version=3;";
 
        // 創(chuàng)建數(shù)據(jù)庫和表
        using (var connection = new SQLiteConnection(connectionString))
        {
            connection.Open();
            string createTableQuery = @"
                CREATE TABLE IF NOT EXISTS FilePaths (
                    id INTEGER PRIMARY KEY AUTOINCREMENT,
                    name TEXT NOT NULL,
                    path TEXT NOT NULL
                );";
            using (var command = new SQLiteCommand(createTableQuery, connection))
            {
                command.ExecuteNonQuery();
            }
        }
 
        // 插入文件路徑
        string filePath = "example.pdf"; // 替換為你的文件路徑
        InsertFilePath(filePath, connectionString);
 
        // 從數(shù)據(jù)庫讀取文件路徑
        GetFilePath(1, connectionString); // 假設讀取 ID 為 1 的文件路徑
    }
 
    static void InsertFilePath(string filePath, string connectionString)
    {
        string fileName = System.IO.Path.GetFileName(filePath);
 
        using (var connection = new SQLiteConnection(connectionString))
        {
            connection.Open();
            string insertQuery = "INSERT INTO FilePaths (name, path) VALUES (@name, @path)";
            using (var command = new SQLiteCommand(insertQuery, connection))
            {
                command.Parameters.AddWithValue("@name", fileName);
                command.Parameters.AddWithValue("@path", filePath);
                command.ExecuteNonQuery();
            }
        }
 
        Console.WriteLine($"File path '{filePath}' has been saved to the database.");
    }
 
    static void GetFilePath(int fileId, string connectionString)
    {
        using (var connection = new SQLiteConnection(connectionString))
        {
            connection.Open();
            string selectQuery = "SELECT name, path FROM FilePaths WHERE id = @id";
            using (var command = new SQLiteCommand(selectQuery, connection))
            {
                command.Parameters.AddWithValue("@id", fileId);
                using (var reader = command.ExecuteReader())
                {
                    if (reader.Read())
                    {
                        string fileName = reader.GetString(0);
                        string filePath = reader.GetString(1);
 
                        Console.WriteLine($"File '{fileName}' is located at '{filePath}'.");
                    }
                }
            }
        }
    }
}

3. 分塊存儲文件

示例代碼:

using System;
using System.Data.SQLite;
using System.IO;
 
class Program
{
    static void Main(string[] args)
    {
        string databasePath = "example.db";
        string connectionString = $"Data Source={databasePath};Version=3;";
 
        // 創(chuàng)建數(shù)據(jù)庫和表
        using (var connection = new SQLiteConnection(connectionString))
        {
            connection.Open();
            string createTableQuery = @"
                CREATE TABLE IF NOT EXISTS FileChunks (
                    id INTEGER PRIMARY KEY AUTOINCREMENT,
                    file_id INTEGER NOT NULL,
                    chunk_index INTEGER NOT NULL,
                    chunk_data BLOB NOT NULL
                );";
            using (var command = new SQLiteCommand(createTableQuery, connection))
            {
                command.ExecuteNonQuery();
            }
        }
 
        // 插入文件分塊
        string filePath = "example.pdf"; // 替換為你的文件路徑
        InsertFileChunks(filePath, 1, connectionString); // 假設文件 ID 為 1
 
        // 重新組裝文件
        ReassembleFile(1, "output.pdf", connectionString); // 輸出為 output.pdf
    }
 
    static void InsertFileChunks(string filePath, int fileId, string connectionString)
    {
        int chunkSize = 1024 * 1024; // 每塊大小為 1MB
        byte[] buffer = new byte[chunkSize];
        int chunkIndex = 0;
 
        using (var fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read))
        using (var connection = new SQLiteConnection(connectionString))
        {
            connection.Open();
            string insertQuery = "INSERT INTO FileChunks (file_id, chunk_index, chunk_data) VALUES (@file_id, @chunk_index, @chunk_data)";
            using (var command = new SQLiteCommand(insertQuery, connection))
            {
                int bytesRead;
                while ((bytesRead = fileStream.Read(buffer, 0, chunkSize)) > 0)
                {
                    byte[] chunkData = new byte[bytesRead];
                    Array.Copy(buffer, chunkData, bytesRead);
 
                    command.Parameters.Clear();
                    command.Parameters.AddWithValue("@file_id", fileId);
                    command.Parameters.AddWithValue("@chunk_index", chunkIndex++);
                    command.Parameters.AddWithValue("@chunk_data", chunkData);
                    command.ExecuteNonQuery();
                }
            }
        }
 
        Console.WriteLine($"File '{filePath}' has been stored in chunks.");
    }
 
    static void ReassembleFile(int fileId, string outputPath, string connectionString)
    {
        using (var connection = new SQLiteConnection(connectionString))
        {
            connection.Open();
            string selectQuery = "SELECT chunk_data FROM FileChunks WHERE file_id = @file_id ORDER BY chunk_index";
            using (var command = new SQLiteCommand(selectQuery, connection))
            {
                command.Parameters.AddWithValue("@file_id", fileId);
                using (var reader = command.ExecuteReader())
                using (var outputFile = new FileStream(outputPath, FileMode.Create, FileAccess.Write))
                {
                    while (reader.Read())
                    {
                        byte[] chunkData = (byte[])reader["chunk_data"];
                        outputFile.Write(chunkData, 0, chunkData.Length);
                    }
                }
            }
        }
 
        Console.WriteLine($"File has been reassembled to '{outputPath}'.");
    }
}

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