C# 向数据库插入/更新数据的最佳方式是什么

鉴于我们有下表：

CREATE TABLE TestData 
(
    ID INT NOT NULL PRIMARY KEY,
    Value INT
)

在将数据写入表时，如果ID已经存在，我将尝试

更新表，或者
插入一个新行

我在生产代码中编写或遇到了几个选项：

首先执行
更新
查询，如果没有更新行，则执行
插入
查询

int affectedRows = 0;
using (IDbCommand updateCmd = new SqlCommand("UPDATE TestData SET Value = @Value WHERE ID = @ID", myConn))
{
    try
    {
        // ...add params
        affectedRows = updateCmd.ExecuteNonQuery();
    }
    catch (SqlException) { /*...*/ }
}

if (affectedRows == 0)
{
    using (IDbCommand insertCmd = new SqlCommand("INSERT INTO TestData VALUES (@ID, @Value)", myConn))
    {
        try
        {
            // ...add params
            affectedRows = insertCmd.ExecuteNonQuery();
        }
        catch (SqlException) { /*...*/ }
    }
}  

int affectedRows = 0;
using (IDbCommand insertCmd = new SqlCommand("INSERT INTO TestData VALUES (@ID, @Value)", myConn))
{
    try
    {
        // ... add params
        affectedRows = insertCmd.ExecuteNonQuery();
    }
    catch (SqlException) { /*...*/ }
}

if (affectedRows == 0)
{
    using (IDbCommand updateCmd = new SqlCommand("UPDATE TestData SET Value = @Value WHERE ID = @ID", myConn))
    {
        try
        {
            // ...add params
            affectedRows = updateCmd.ExecuteNonQuery();
        }
        catch (SqlException) { /*...*/ }
    }
}

bool dataExist = false;
// ... 
using (IDbCommand selectCmd = new SqlCommand("SELECT ID FROM TestDate WHERE ID=@ID", myConn))
{
    try
    {
        // ... add param
        using (IDataReader reader = selectCmd.ExecuteReader())
            dataExist = reader.Read();
    }
    catch (SqlException) { /*...*/ }
}
if (dataExist) { /* update query, similar to above one*/ }
else { /* insert, similar to above one */ }

首先执行
Insert
查询，如果失败，则执行
Insert
查询

int affectedRows = 0;
using (IDbCommand updateCmd = new SqlCommand("UPDATE TestData SET Value = @Value WHERE ID = @ID", myConn))
{
    try
    {
        // ...add params
        affectedRows = updateCmd.ExecuteNonQuery();
    }
    catch (SqlException) { /*...*/ }
}

if (affectedRows == 0)
{
    using (IDbCommand insertCmd = new SqlCommand("INSERT INTO TestData VALUES (@ID, @Value)", myConn))
    {
        try
        {
            // ...add params
            affectedRows = insertCmd.ExecuteNonQuery();
        }
        catch (SqlException) { /*...*/ }
    }
}  

int affectedRows = 0;
using (IDbCommand insertCmd = new SqlCommand("INSERT INTO TestData VALUES (@ID, @Value)", myConn))
{
    try
    {
        // ... add params
        affectedRows = insertCmd.ExecuteNonQuery();
    }
    catch (SqlException) { /*...*/ }
}

if (affectedRows == 0)
{
    using (IDbCommand updateCmd = new SqlCommand("UPDATE TestData SET Value = @Value WHERE ID = @ID", myConn))
    {
        try
        {
            // ...add params
            affectedRows = updateCmd.ExecuteNonQuery();
        }
        catch (SqlException) { /*...*/ }
    }
}

bool dataExist = false;
// ... 
using (IDbCommand selectCmd = new SqlCommand("SELECT ID FROM TestDate WHERE ID=@ID", myConn))
{
    try
    {
        // ... add param
        using (IDataReader reader = selectCmd.ExecuteReader())
            dataExist = reader.Read();
    }
    catch (SqlException) { /*...*/ }
}
if (dataExist) { /* update query, similar to above one*/ }
else { /* insert, similar to above one */ }

首先使用新ID执行
选择
查询，然后如果行存在，则执行
更新
其他
插入
查询

int affectedRows = 0;
using (IDbCommand updateCmd = new SqlCommand("UPDATE TestData SET Value = @Value WHERE ID = @ID", myConn))
{
    try
    {
        // ...add params
        affectedRows = updateCmd.ExecuteNonQuery();
    }
    catch (SqlException) { /*...*/ }
}

if (affectedRows == 0)
{
    using (IDbCommand insertCmd = new SqlCommand("INSERT INTO TestData VALUES (@ID, @Value)", myConn))
    {
        try
        {
            // ...add params
            affectedRows = insertCmd.ExecuteNonQuery();
        }
        catch (SqlException) { /*...*/ }
    }
}  

int affectedRows = 0;
using (IDbCommand insertCmd = new SqlCommand("INSERT INTO TestData VALUES (@ID, @Value)", myConn))
{
    try
    {
        // ... add params
        affectedRows = insertCmd.ExecuteNonQuery();
    }
    catch (SqlException) { /*...*/ }
}

if (affectedRows == 0)
{
    using (IDbCommand updateCmd = new SqlCommand("UPDATE TestData SET Value = @Value WHERE ID = @ID", myConn))
    {
        try
        {
            // ...add params
            affectedRows = updateCmd.ExecuteNonQuery();
        }
        catch (SqlException) { /*...*/ }
    }
}

bool dataExist = false;
// ... 
using (IDbCommand selectCmd = new SqlCommand("SELECT ID FROM TestDate WHERE ID=@ID", myConn))
{
    try
    {
        // ... add param
        using (IDataReader reader = selectCmd.ExecuteReader())
            dataExist = reader.Read();
    }
    catch (SqlException) { /*...*/ }
}
if (dataExist) { /* update query, similar to above one*/ }
else { /* insert, similar to above one */ }

执行一个大查询以执行所有选择更新或插入操作

string query = "IF EXISTS (SELECT ID FROM TestData WHERE ID=@ID) " +
               "UPDATE TestData SET Value = @Value WHERE ID = @ID " +
               "ELSE INSERT INTO TestData VALUES (@ID, @Value)";

using (IDbCommand bigQueryCmd = new SqlCommand(query, myConn))
{
    try
    {
        // ... add param
        bigQueryCmd.ExecuteNonQuery();
    }
    catch (SqlException) { /*...*/ }
}

我的问题是，在上述选项（或您自己的方法）中，什么是
最佳实践
或
最有效的
或
首选方法

上述选项的示例代码：

（1） 首先执行
更新
查询，如果没有更新行，则执行
插入
查询

int affectedRows = 0;
using (IDbCommand updateCmd = new SqlCommand("UPDATE TestData SET Value = @Value WHERE ID = @ID", myConn))
{
    try
    {
        // ...add params
        affectedRows = updateCmd.ExecuteNonQuery();
    }
    catch (SqlException) { /*...*/ }
}

if (affectedRows == 0)
{
    using (IDbCommand insertCmd = new SqlCommand("INSERT INTO TestData VALUES (@ID, @Value)", myConn))
    {
        try
        {
            // ...add params
            affectedRows = insertCmd.ExecuteNonQuery();
        }
        catch (SqlException) { /*...*/ }
    }
}  

int affectedRows = 0;
using (IDbCommand insertCmd = new SqlCommand("INSERT INTO TestData VALUES (@ID, @Value)", myConn))
{
    try
    {
        // ... add params
        affectedRows = insertCmd.ExecuteNonQuery();
    }
    catch (SqlException) { /*...*/ }
}

if (affectedRows == 0)
{
    using (IDbCommand updateCmd = new SqlCommand("UPDATE TestData SET Value = @Value WHERE ID = @ID", myConn))
    {
        try
        {
            // ...add params
            affectedRows = updateCmd.ExecuteNonQuery();
        }
        catch (SqlException) { /*...*/ }
    }
}

bool dataExist = false;
// ... 
using (IDbCommand selectCmd = new SqlCommand("SELECT ID FROM TestDate WHERE ID=@ID", myConn))
{
    try
    {
        // ... add param
        using (IDataReader reader = selectCmd.ExecuteReader())
            dataExist = reader.Read();
    }
    catch (SqlException) { /*...*/ }
}
if (dataExist) { /* update query, similar to above one*/ }
else { /* insert, similar to above one */ }

（2） 首先执行
Insert
查询，如果失败，则执行
Insert
查询

int affectedRows = 0;
using (IDbCommand updateCmd = new SqlCommand("UPDATE TestData SET Value = @Value WHERE ID = @ID", myConn))
{
    try
    {
        // ...add params
        affectedRows = updateCmd.ExecuteNonQuery();
    }
    catch (SqlException) { /*...*/ }
}

if (affectedRows == 0)
{
    using (IDbCommand insertCmd = new SqlCommand("INSERT INTO TestData VALUES (@ID, @Value)", myConn))
    {
        try
        {
            // ...add params
            affectedRows = insertCmd.ExecuteNonQuery();
        }
        catch (SqlException) { /*...*/ }
    }
}  

int affectedRows = 0;
using (IDbCommand insertCmd = new SqlCommand("INSERT INTO TestData VALUES (@ID, @Value)", myConn))
{
    try
    {
        // ... add params
        affectedRows = insertCmd.ExecuteNonQuery();
    }
    catch (SqlException) { /*...*/ }
}

if (affectedRows == 0)
{
    using (IDbCommand updateCmd = new SqlCommand("UPDATE TestData SET Value = @Value WHERE ID = @ID", myConn))
    {
        try
        {
            // ...add params
            affectedRows = updateCmd.ExecuteNonQuery();
        }
        catch (SqlException) { /*...*/ }
    }
}

bool dataExist = false;
// ... 
using (IDbCommand selectCmd = new SqlCommand("SELECT ID FROM TestDate WHERE ID=@ID", myConn))
{
    try
    {
        // ... add param
        using (IDataReader reader = selectCmd.ExecuteReader())
            dataExist = reader.Read();
    }
    catch (SqlException) { /*...*/ }
}
if (dataExist) { /* update query, similar to above one*/ }
else { /* insert, similar to above one */ }

（3） 首先使用新ID执行
选择
查询，然后如果行存在，则执行
更新
其他
插入
查询

int affectedRows = 0;
using (IDbCommand updateCmd = new SqlCommand("UPDATE TestData SET Value = @Value WHERE ID = @ID", myConn))
{
    try
    {
        // ...add params
        affectedRows = updateCmd.ExecuteNonQuery();
    }
    catch (SqlException) { /*...*/ }
}

if (affectedRows == 0)
{
    using (IDbCommand insertCmd = new SqlCommand("INSERT INTO TestData VALUES (@ID, @Value)", myConn))
    {
        try
        {
            // ...add params
            affectedRows = insertCmd.ExecuteNonQuery();
        }
        catch (SqlException) { /*...*/ }
    }
}  

int affectedRows = 0;
using (IDbCommand insertCmd = new SqlCommand("INSERT INTO TestData VALUES (@ID, @Value)", myConn))
{
    try
    {
        // ... add params
        affectedRows = insertCmd.ExecuteNonQuery();
    }
    catch (SqlException) { /*...*/ }
}

if (affectedRows == 0)
{
    using (IDbCommand updateCmd = new SqlCommand("UPDATE TestData SET Value = @Value WHERE ID = @ID", myConn))
    {
        try
        {
            // ...add params
            affectedRows = updateCmd.ExecuteNonQuery();
        }
        catch (SqlException) { /*...*/ }
    }
}

bool dataExist = false;
// ... 
using (IDbCommand selectCmd = new SqlCommand("SELECT ID FROM TestDate WHERE ID=@ID", myConn))
{
    try
    {
        // ... add param
        using (IDataReader reader = selectCmd.ExecuteReader())
            dataExist = reader.Read();
    }
    catch (SqlException) { /*...*/ }
}
if (dataExist) { /* update query, similar to above one*/ }
else { /* insert, similar to above one */ }

（4） 执行一个大查询以执行所有选择更新或插入操作

string query = "IF EXISTS (SELECT ID FROM TestData WHERE ID=@ID) " +
               "UPDATE TestData SET Value = @Value WHERE ID = @ID " +
               "ELSE INSERT INTO TestData VALUES (@ID, @Value)";

using (IDbCommand bigQueryCmd = new SqlCommand(query, myConn))
{
    try
    {
        // ... add param
        bigQueryCmd.ExecuteNonQuery();
    }
    catch (SqlException) { /*...*/ }
}

您可以使用

基于目标表对目标表执行插入、更新或删除操作
关于与源表联接的结果

出于并发原因，使用
MERGE比
如果存在/UPDATE/INSERT
要好得多，而且它只是一条语句，因此需要维护的代码更少：

比如：


CREATE TABLE TestData (
   ID INT NOT NULL PRIMARY KEY,
   Value INT);

INSERT INTO TestData
VALUES (1,3);


DECLARE @id INT = 1, @value INT = 10;    -- will update
--DECLARE @id INT = 2, @value INT = 10;  -- will insert

;MERGE TestData AS TGT
USING (SELECT * FROM (SELECT @id AS ID, @value AS VALUE) AS t) AS SRC
   ON TGT.ID = SRC.ID
WHEN MATCHED THEN
   UPDATE SET Value = SRC.[VALUE]
WHEN NOT MATCHED THEN
   INSERT (ID, [VALUE])
   VALUES (SRC.ID, SRC.[VALUE]);

SELECT *
FROM TestData;

检查您是否可以为我使用
MERGE
。没有，因为您的代码很容易被SQL注入！如果您克服了这个问题，那么您可以创建一个存储过程，并在其中创建更新和插入逻辑。这是一个直接向表中插入新数据的过程。我应该从哪里合并？与派生表合并这是从C#调用的一个大查询吗？是的，您需要绑定参数，它应该可以工作。但首先使用SSMSI检查是否知道合并会起作用，问题是它是否比其他方法更好。我发现它非常类似于第四个选项（如果存在/UPDATE/INSERT）@VietNguyen MERGE只是一条语句，使用隐式事务完成。如果您有并发应用程序，并且在存在/更新/插入时使用多部分，该怎么办。一个查询可以在另一个查询插入数据时检查是否存在