如何将文件存储到数据库中？

Question

如何将用户上传的文件存储到数据库中？我想将文件存储在数据库中我们该怎么做？在后端，我将 sql 与 c#.net 应用程序一起使用。

Answer 1

此解决方案适用于 SQL SERVER 2005/2008。

您必须创建表作为VARBINARY(MAX)列之一。就我而言，我创建了表Raporty，其中RaportPlik列为VARBINARY(MAX)列。

下面有几个支持功能，您可以根据需要进行修改：

    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();
        }
    }
    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);
                }
        }
    }
    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);
                    //using (var fs = new MemoryStream(memoryStream, FileMode.Create, FileAccess.Write)) {
                    memoryStream.Write(blob, 0, blob.Length);
                    //}
                }
        }
        return memoryStream;
    }

第一种方法是将文件从驱动器放入数据库，第二种方法是获取文件并将其保存在驱动器上，第三种方法是从数据库获取文件并将其放入，以便MemoryStream您可以使用它进行其他操作，然后将其写入驱动器。

第四种方法是放入MemoryStream数据库：

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;
    }