Question

我在Visual Studio中遇到UPDATE命令有问题我明白了。

我有一个MS Access关系数据库后端，我已经在vb中连接它，我可以显示记录等但是我无法让它更新。我在Form_Load

中有这个

Dim strQuery As String = "SELECT ContractID AS [Contract ID], ProductName AS [Product Name], SigningDate AS [Date Signed], StartDate AS [Start Date], EndDate AS [End Date] FROM ((PolicyContract) INNER JOIN Clients on PolicyContract.ClientID = Clients.ClientID) INNER Join Products on PolicyContract.ProductID = Products.ProductID WHERE PolicyContract.ClientID = '" + clientID + "' ORDER BY PolicyContract.ContractID;"

    'initialise the data adapter
    daPolicyContract = New OleDbDataAdapter(strQuery, connection)
    'initialise the dataset
    dsAllroundInsurance = New DataSet
    'fill the dataset
    daPolicyContract.Fill(dsAllroundInsurance, "PolicyContract")

    'bind data grid to data in PolicyContract table
    dgvPolicies.DataSource = dsAllroundInsurance.Tables("PolicyContract")
    'autosize columns to fit grid size
    dgvPolicies.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.Fill

它工作正常，它显示正确的记录，但我想更新记录当我单击一个按钮时，我想更新特定合同的“EndDate”值。当我执行此命令时：

UPDATE ((PolicyContract) 
INNER JOIN Clients
ON PolicyContract.ClientID = Clients.ClientID)
INNER JOIN Products
ON PolicyContract.ProductID = Products.ProductID
SET PolicyContract.EndDate = '1/1/1111'
WHERE PolicyContract.ContractID = 'C100102';

在MS Access中它正确更新，所以命令没问题。当我尝试在这样的单击事件处理程序中执行命令时：

daPolicyContract.UpdateCommand = New OleDbCommand("UPDATE ((PolicyContract) INNER JOIN Clients ON PolicyContract.ClientID = Clients.ClientID) INNER JOIN Products ON PolicyContract.ProductID = Products.ProductID SET PolicyContract.EndDate = '1/1/1111' WHERE PolicyContract.ContractID = 'C100102';", connection)

没有任何反应，我没有收到错误，但仍然没有更新。我很确定vb正在执行命令，但它没有更新数据库任何帮助将不胜感激，谢谢。

Answer 1

我无处可见该命令的执行。您必须确保在命令上调用ExecuteNonQuery()。否则它将无法执行。

Visual Studio中的SQL Update命令

1 个答案: