如何检查数据库中的重复条目 [英] how to check for duplicate entry in database
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问题描述
大家好
请告诉我如何在插入数据之前检查数据库列中的重复条目。
i有一个名为company的列姓名(不是主键)
谢谢
Hi all
Please tell me how do i check duplicate entry in databse column before inserting the data.
i have column called company name(not a primary key)
thank you
推荐答案
SqlDataAdapter da = new SqlDataAdapter("SELECT * FROM [company] Where companyname='" + Textbox.Text.Trim() + "'", connection);
DataSet ds = new DataSet();
da.Fill(ds);
if (ds.Tables[0].Rows.Count == 0)
{
MessageBox.Show("Company name Not found");
}else
{
MessageBox.Show("Company name Already exist");
}
Public Function CompanyNameExists(ByVal companyName As String) As Boolean
Dim query As String = "SELECT Count(*) FROM [yourtable] WHERE CompanyName=@CompanyName"
Dim rowCount As Integer
Using conn As New SqlConnection("your sql connection string")
conn.Open()
Using comm As New SqlCommand(query, conn)
comm.Parameters.AddWithValue("@CompanyName", companyName)
rowCount = Convert.ToInt32(comm.ExecuteScalar())
End Using
End Using
Return (rowCount > 0)
End Function
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