将文件转换为字节数组是数据库存储的最佳解决方案吗？-C++-PHP中文网

将文件转换为字节数组是数据库存储的最佳解决方案吗？

Patricia Arquette

发布： 2025-01-15 08:56:44

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Is Converting Files to Byte Arrays the Optimal Solution for Database Storage?

将文件转换为字节数组：数据库存储的最佳方案？

问题

将文件存储到数据库或磁盘中，需要考虑最有效和可靠的方法。一种方法是在保存文件之前将其转换为字节数组。本文探讨将文件转换为字节数组是否为存储任何文件格式的最佳策略。

解释

将文件转换为字节数组以进行数据库存储的适用性取决于所使用的特定数据库。例如，在 SQL Server 中，使用 VARBINARY(MAX) 列创建表允许有效存储字节数组。

以下 C# 代码演示如何将文件从驱动器存储到数据库中：

<code class="language-csharp">public static void databaseFilePut(string varFilePath) {
    byte[] file;
    using (var stream = new FileStream(varFilePath, FileMode.Open, FileAccess.Read)) {
        using (var reader = new BinaryReader(stream)) {
            file = reader.ReadBytes((int)stream.Length);
        }
    }
    using (var varConnection = Locale.sqlConnectOneTime(Locale.sqlDataConnectionDetails))
    using(var sqlWrite = new SqlCommand("INSERT INTO Raporty (RaportPlik) Values(@File)", varConnection)) {
        sqlWrite.Parameters.Add("@File", SqlDbType.VarBinary, file.Length).Value = file;
        sqlWrite.ExecuteNonQuery();
    }
}</code>

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要检索文件并将其保存到驱动器：

<code class="language-csharp">public static void databaseFileRead(string varID, string varPathToNewLocation) {
    using (var varConnection = Locale.sqlConnectOneTime(Locale.sqlDataConnectionDetails))
    using(var sqlQuery = new SqlCommand(@"SELECT [RaportPlik] FROM [dbo].[Raporty] WHERE [RaportID] = @varID", varConnection)) {
        sqlQuery.Parameters.AddWithValue("@varID", varID);
        using (var sqlQueryResult = sqlQuery.ExecuteReader())
            if(sqlQueryResult != null) {
                sqlQueryResult.Read();
                var blob = new Byte[(sqlQueryResult.GetBytes(0, 0, null, 0, int.MaxValue))];
                sqlQueryResult.GetBytes(0, 0, blob, 0, blob.Length);
                using (var fs = new FileStream(varPathToNewLocation, FileMode.Create, FileAccess.Write)) 
                    fs.Write(blob, 0, blob.Length);
            }
    }
}</code>

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此方法允许将文件作为内存流检索：

<code class="language-csharp">public static MemoryStream databaseFileRead(string varID) {
    MemoryStream memoryStream = new MemoryStream();
    using (var varConnection = Locale.sqlConnectOneTime(Locale.sqlDataConnectionDetails))
    using(var sqlQuery = new SqlCommand(@"SELECT [RaportPlik] FROM [dbo].[Raporty] WHERE [RaportID] = @varID", varConnection)) {
        sqlQuery.Parameters.AddWithValue("@varID", varID);
        using (var sqlQueryResult = sqlQuery.ExecuteReader())
            if (sqlQueryResult != null) {
                sqlQueryResult.Read();
                var blob = new Byte[(sqlQueryResult.GetBytes(0, 0, null, 0, int.MaxValue))];
                sqlQueryResult.GetBytes(0, 0, blob, 0, blob.Length);
                memoryStream.Write(blob, 0, blob.Length);
            }
    }
    return memoryStream;
}</code>

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最后，将内存流插入数据库：

<code class="language-csharp">public static int databaseFilePut(MemoryStream fileToPut) {
    int varID = 0;
    byte[] file = fileToPut.ToArray();
    const string preparedCommand = @"
                    INSERT INTO [dbo].[Raporty]
                               ([RaportPlik])
                         VALUES
                               (@File)
                        SELECT [RaportID] FROM [dbo].[Raporty]
            WHERE [RaportID] = SCOPE_IDENTITY()
                    ";
    using (var varConnection = Locale.sqlConnectOneTime(Locale.sqlDataConnectionDetails))
    using (var sqlWrite = new SqlCommand(preparedCommand, varConnection)) {
        sqlWrite.Parameters.Add("@File", SqlDbType.VarBinary, file.Length).Value = file;

        using (var sqlWriteQuery = sqlWrite.ExecuteReader())
            while (sqlWriteQuery != null && sqlWriteQuery.Read()) {
                varID = sqlWriteQuery["RaportID"] is int ? (int)sqlWriteQuery["RaportID"] : 0;
            }
    }
    return varID;
}</code>

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