[英]How to prevent Sqlite Database is locked?
我在數據庫上讀了一個線程。 當我點擊menustrip時,它顯示錯誤“數據庫被鎖定”。 它有時只會發生。 有什么方法可以防止數據庫鎖定? 我試過WAL但它不起作用。
讀:
private void checkPort(string ipIN, char[] input, string output)
{
try
{
bool building = false;
Thread beep = new Thread(Beep);
using (SQLiteConnection c = new SQLiteConnection(dbconnection))
{
c.Open();
string query = "select * from ALL_IO(nolock)";
using (SQLiteCommand cmd = new SQLiteCommand(query, c))
{
using (SQLiteDataReader dr = cmd.ExecuteReader())
{
int Contact;
while (dr.Read())
{
string _IP = dr.GetString(0);
string _IO_I = dr.GetString(1);
string _BuildingName = dr.GetString(4);
int IO_I = Convert.ToInt32(dr.GetString(1).Replace("DI ", ""));
if (dr.GetString(3) == "NC")
{
Contact = 1;
}
else
{
Contact = 0;
}
_tableName = dr.GetString(8);
string _name = dr.GetString(5);
var _active = dr.GetString(6);
var _status = dr.GetString(7);
if (_active == "Yes" && _status == "Enable")
{
//Some condition check here
}
}
catch { }
}
寫作:
void contexMenuuu_ItemClicked(object sender, ToolStripItemClickedEventArgs e)
{
data = "";
ToolStripItem item = e.ClickedItem;
using (SQLiteConnection c = new SQLiteConnection(dbconnection))
{
c.Open();
string sql = "select * from " + Properties.Settings.Default.TableName + "(nolock) where Name= '" + Properties.Settings.Default.LabelName.Replace(" DO", "") + "' ";
using (SQLiteCommand cmd = new SQLiteCommand(sql, c))
{
using (SQLiteDataReader dr = cmd.ExecuteReader())
{
while (dr.Read())
{
_controllerIP = dr.GetString(0);
_IO = dr.GetString(1);
_IO_O = dr.GetString(2).Replace("DO ", "");
_Name = dr.GetString(4);
_Interval = Convert.ToInt32(dr.GetString(9));
}
}
}
}
if (item.Text == "Bypass Enable")
{
using (SQLiteConnection c = new SQLiteConnection(dbconnection))
{
//c.DefaultTimeout = 2000;
c.Open();
string sql = "update ALL_IO SET Active='Yes', Status='Bypass' where ControllerIP='" + _controllerIP + "' and DI='" + _IO + "';";
using (SQLiteCommand cmd = new SQLiteCommand(sql, c))
{
lock (lockobj)
{
//SQLiteConnection.ClearAllPools();
cmd.ExecuteNonQuery(); //Error occur here
}
}
}
}
功能完成后,您必須關閉數據庫連接以避免數據庫鎖定問題。 為了執行查詢,您打開了數據庫連接,之后您沒有關閉它。 所以你需要關閉。
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