在Linux平台下使用.NET Core访问Access数据库读取mdb文件数据

夺目 · 发表于 2023-11-22 18:01:05

今天有群友在群里问 C# 能不能在 Linux 下访问 Access数据库？
我觉得这很有趣，因此研究折腾了一下，也因为很久没有写博文了，所以特意上来写博文分享经验。
运行环境

操作系统：Ubuntu 22.04.3 LTS (Jammy)
开发工具：Visual Studio 2022 (17.8.0)
运行时版本：.NET Runtime 8.0
依赖库：unixodbc、mdbtools、odbc-mdbtools

依赖库安装

apt-get update
sudo apt-get install unixodbc mdbtools odbc-mdbtools

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依赖库版本信息

apt list --installed | grep odbc

libodbc1/jammy,now 2.3.9-5 amd64 [installed,automatic]
libodbc2/jammy,now 2.3.9-5 amd64 [installed,automatic]
libodbccr2/jammy,now 2.3.9-5 amd64 [installed,automatic]
libodbcinst2/jammy,now 2.3.9-5 amd64 [installed,automatic]
odbc-mdbtools/jammy,now 1.0.0+dfsg-1 amd64 [installed]
odbcinst1debian2/jammy,now 2.3.9-5 amd64 [installed,automatic]
odbcinst/jammy,now 2.3.9-5 amd64 [installed,automatic]
unixodbc-common/jammy,now 2.3.9-5 all [installed,automatic]
unixodbc/jammy,now 2.3.9-5 amd64 [installed]

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apt list --installed | grep mdb

liblmdb0/jammy,now 0.9.24-1build2 amd64 [installed,automatic]
libmdb3/jammy,now 1.0.0+dfsg-1 amd64 [installed,automatic]
libmdbsql3/jammy,now 1.0.0+dfsg-1 amd64 [installed,automatic]
mdbtools/jammy,now 1.0.0+dfsg-1 amd64 [installed]
odbc-mdbtools/jammy,now 1.0.0+dfsg-1 amd64 [installed]

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Linux平台下的 ODBC 配置

/etc/odbc.ini

[access_db] # 随意命名，会在项目代码里用到它
Description=Microsoft Access Database
Driver=MDBW
ServerName = localhost
Database=/root/Database1.mdb # 按你的实际路径改写，要有读写权限

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/etc/odbcinst.ini

[MDBW] # 随意，在odbc.ini文件用到它
Description=MDBTools Driver Wide # 随意
Driver=/usr/lib/x86_64-linux-gnu/odbc/libmdbodbcW.so # 按你的实际路径改写
Setup=/usr/lib/x86_64-linux-gnu/odbc/libmdbodbcW.so # 按你的实际路径改写
FileUsage=1
UsageCount=1
[MDBTools]
Description=MDBTools Driver # 随意
Driver=/usr/lib/x86_64-linux-gnu/odbc/libmdbodbc.so # 按你的实际路径改写
Setup=/usr/lib/x86_64-linux-gnu/odbc/libmdbodbc.so # 按你的实际路径改写
FileUsage=1
UsageCount=1
[ODBC]
Trace=1
TraceFile=/tmp/mdb.log # 有写入权限的文件路径

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Demo 项目代码

OdbcForLinuxTestApp.csproj

<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<OutputType>Exe</OutputType>
<TargetFramework>net8.0</TargetFramework>
<ImplicitUsings>enable</ImplicitUsings>
<Nullable>enable</Nullable>
<RuntimeIdentifiers>linux-x64;win-x64</RuntimeIdentifiers>
<SelfContained>true</SelfContained>
<ProduceReferenceAssembly>false</ProduceReferenceAssembly>
<AppendRuntimeIdentifierToOutputPath>false</AppendRuntimeIdentifierToOutputPath>
<AppendTargetFrameworkToOutputPath>false</AppendTargetFrameworkToOutputPath>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="System.Data.Odbc" Version="8.0.0" />
<PackageReference Include="System.Data.OleDb" Version="8.0.0" />
</ItemGroup>
</Project>

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Program.cs

using System.Data;
using System.Data.Common;
using System.Data.Odbc;
using System.Data.OleDb;
namespace OdbcForLinuxTestApp;
internal sealed class Program
{
static async Task Main(string[] args)
{
string connectionStrings;
if (OperatingSystem.IsWindows())
{
string mdbFile = Path.Combine(AppContext.BaseDirectory, "Database1.mdb");
connectionStrings = $"Provider=Microsoft.ACE.OLEDB.12.0;Data Source={mdbFile}";
}
else
{
//root/Database1.mdb
connectionStrings = "DSN=access_db;";
}
await using (DbConnection conn = GetDbConnection(connectionStrings))
{
await conn.OpenAsync();
DbCommand cmd = conn.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "select [ID],[UserName] from Users";
DbDataReader reader = await cmd.ExecuteReaderAsync();
while (await reader.ReadAsync())
{
//The MDBTools does not support the use of column names
string userName = reader.GetString(1);
Console.WriteLine("UserName: " + userName);
}
}
}
private static string DbProviderName => OperatingSystem.IsWindows() ? "System.Data.OleDb" : "System.Data.Odbc";
private static DbConnection GetDbConnection(string connectionStrings)
{
RegisterOdbcOrOleDbFactory();
DbProviderFactory dbFactory = DbProviderFactories.GetFactory(DbProviderName);
DbConnection? conn = dbFactory.CreateConnection();
if (conn == null)
{
return OperatingSystem.IsWindows() ? new OleDbConnection(connectionStrings) : new OdbcConnection(connectionStrings);
}
conn.ConnectionString = connectionStrings;
return conn;
}
private static int _isRegisteredDbFactory;
private static void RegisterOdbcOrOleDbFactory()
{
if (Interlocked.CompareExchange(ref _isRegisteredDbFactory, 1, 0) == 0)
{
string dbProviderName = DbProviderName;
IEnumerable<string> providerInvariantNames = DbProviderFactories.GetProviderInvariantNames();
string? invariantName = providerInvariantNames.FirstOrDefault(x => x.Equals(dbProviderName, StringComparison.InvariantCultureIgnoreCase));
if (string.IsNullOrWhiteSpace(invariantName))
{
DbProviderFactories.RegisterFactory(dbProviderName, OdbcFactory.Instance);
}
}
}
}

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编译和发布 Demo 项目代码

准备工作

创建 OdbcForLinuxTestApp 目录
将上述两个代码文件放入 OdbcForLinuxTestApp 目录
安装 .NET SDK 8.0.100

编译和发布

在 OdbcForLinuxTestApp 目录下，执行命令：

dotnet publish -c Release -f net8.0 -r win-x64 -o ./publish/win-x64 # 如果只考虑 Linux平台，该命令可忽略
dotnet publish -c Release -f net8.0 -r linux-x64 -o ./publish/linux-x64

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运行 OdbcForLinuxTestApp

注意：Database1.mdb 数据库文件需要提前放到正确的路径，以 odbc.ini文件的 Database 配置项为准。

cd ./publish/linux-x64
chmod +x OdbcForLinuxTestApp # 授予可执行权限
./OdbcForLinuxTestApp

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输出：

UserName: Allen
UserName: Joy

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折腾过程中遇到的问题

搜了几个配置例子，有的说 libmdbodbc.so 在 /usr/lib 目录下，
也有的在 /usr/local/lib/odbc 目录下，而我最终是在 /usr/lib/x86_64-linux-gnu/odbc 目录下找到。
mdbtools 不支持使用列名访问，只能用列索引。

其它

参考：https://github.com/mdbtools/mdbtools/issues/347
MDB Tools：https://mdbtools.github.io

来源:https://www.cnblogs.com/VAllen/archive/2023/11/22/access-mdb-files-in-linux.html
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