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how can I get the id back from an access insert query? [duplicate]

This question already has answers here:
Autonumber value of last inserted row - MS Access / VBA
(5 answers)
Closed 5 years ago.
I have an access data base where i want to add a row in a table. but I want to get the id(colum name -> id) back.
this is the code i use to register a new group:
int id;
internal static void agregarGrupo(int grado, char grupo, String escuela, int maestro)
{
try
{
comand.Connection = conection;
comand.CommandText =
"INSERT INTO Grupos " +
"(grado, grupo, escuela, maestro) " +
"VALUES(" + grado + ", '" + grupo + "' , '" + escuela + "', " + maestro + ")";
conection.Open();
id = comand.ExecuteScalar();
}
finally
{
conection.Close();
}
}
what am I doing wrong?
how can I get the id of the new row without making a new query asking for the bigest id in the table?

You have to make another query to get the last identity value inserted because Access does not support batch commands. You need to reuse the connection and issue another command like this:
string query = "SELECT ##IDENTITY";
var cmd = new OleDbCommand(query, (OleDbConnection)command.Connection);
int newId = (int)cmd.ExecuteScalar();
Or you can simply do this after this line of code you have:
id = comand.ExecuteScalar(); // this is your code
command.CommandText = "SELECT ##IDENTITY";
int newId = (int)command.ExecuteScalar();

C# Exception thrown: 'System.Data.SqlClient.SqlException' in System.Data.dll

Apologies in advance if I missed an answer to this somewhere but I wasn't quite finding it anywhere. So I'm building an application that scans PDF's of service orders our company gets, parses it, and inserts it into a SQL DB. The problem is at the end of this code. It successfully :
saves the original pdf in the proper folder
scans the pdf and parses it
inserts the correct data into the service order table
grabs PK of service order just created as we need that for the next batch of inserts
Here is where it gets hung up with a Exception thrown: 'System.Data.SqlClient.SqlException' in System.Data.dll
I foreach through all the instruments as there are multiples per Service Order, but it is erroring on this somewhere. to be clear I put a break point on the insert statement and all of the data is good and in the proper format ("string" int)
I feel like its in my connection maybe?
Anyways, thanks in advance for the help.
string filename = Path.GetFileName(FileUpload1.FileName);
FileUpload1.SaveAs(Server.MapPath("~/PDF/") + filename);
// Now we parse the PDF by creating a new ServiceOrder object and parsing from it.
ServiceOrder so = new ServiceOrder();
// Make sure we load the PDF from the correct path on the server
so.LoadPDF(Server.MapPath("~/PDF/") + filename);
String strConnString = "Data Source=127.0.0.0;Initial Catalog=SOMECATALOG;User ID=SOMEUSER;Password=SOMEPASSWORD";
// Insert Into Service Orders Table
string defaultdate = DateTime.Now.ToString("yyyy-MM-dd");
String strQuery = "insert into TServiceOrders (strServiceOrderNo, intStatusCodeID, strCustomerName, strCustomerNo, strCustomerAddress1, strCustomerAddress2, strCustomerAddress3, intRepID, strServiceDescription, strServiceRequestDate, strServiceOrderDate, strNotes) values ('"
+ so.ServiceOrderNumber.ToString() + "', 2, '"
+ so.CustomerContactName.ToString() + "', '"
+ so.CustomerNumber.ToString() + "', '"
+ so.CustomerContactAddress1.ToString() + "', '"
+ so.CustomerContactAddress2.ToString() + "', '"
+ so.CustomerContactAddress3.ToString() + "', 1, '', '"
+ defaultdate + "', '" + defaultdate + "', '')";
SqlConnection conn = new SqlConnection(strConnString);
SqlCommand cmd = new SqlCommand(strQuery, conn);
conn.Open();
cmd.ExecuteNonQuery();
conn.Close();
// Grabbing latest primary key od service order just added for next instrument inserts
int lastid = 999999;
String strPKquery = "select top 1 intServiceOrderID from TServiceOrders order by intServiceOrderID desc";
SqlDataReader rdr = null;
SqlConnection conn2 = new SqlConnection(strConnString);
SqlCommand cmd2 = new SqlCommand(strPKquery, conn2);
try
{
conn2.Open();
rdr = cmd2.ExecuteReader();
while (rdr.Read())
{
lastid = (int)rdr["intServiceOrderID"];
}
}
finally
{
if (rdr != null)
{
rdr.Close();
}
if (conn2 != null)
{
conn2.Close();
}
}
// Insert Into Service Instruments Tables
SqlConnection conn3 = new SqlConnection(strConnString);
conn3.Open();
foreach (ServiceInstrument sin in so.ServiceInstruments)
{
string sim = "";
sim = sin.ServiceInstrumentModel;
if (String.IsNullOrEmpty(sim))
{
sim = "";
}
else
{
sim = sin.ServiceInstrumentModel.ToString();
}
string sid = "";
sid = sin.ServiceInstrumentDescription;
if (String.IsNullOrEmpty(sid))
{
sid = "";
}
else
{
sid = sin.ServiceInstrumentDescription.ToString();
}
string sis = "";
sis = sin.ServiceInstrumentSerial;
if (String.IsNullOrEmpty(sis))
{
sis = "";
}
else
{
sis = sin.ServiceInstrumentSerial.ToString();
}
string sih = "";
sih = sin.ServiceInstrumentHandle;
if (String.IsNullOrEmpty(sih))
{
sih = "";
}
else
{
sih = sin.ServiceInstrumentHandle.ToString();
}
string sip = "";
sip = sin.ServiceInstrumentParentAsset;
if (String.IsNullOrEmpty(sip))
{
sip = "";
}
else
{
sip = sin.ServiceInstrumentParentAsset.ToString();
}
String strQuery3 = "insert into TServiceInstruments values ('" + sim.ToString() + "', '" + sid.ToString() + "', '" + sis.ToString() + "', '" + sih.ToString() + "', " + sip.ToString() + ", " + lastid + ")";
SqlCommand cmd3 = new SqlCommand(strQuery3, conn3);
cmd3.ExecuteNonQuery();
}
conn3.Close();

When writing insert statements you should always specify the column names. This will protect the code from changes in the order of the columns in the table schema.
You are not using parameters in your sql statements, this leaves your code vulnerable to Sql Injection.
You should use using statements around your SqlConnection instances to ensure they are closed even when an Exception occurs.
Your logic is very difficult to follow, split your code until methods with meaningful names instead of having 1 "God" method that does everything.
If you follow those guidelines the problem will most likely solve itself in your refactoring.
Update Code Fragment
Note that you should always specify the correct types for your columns and the length if applicable. Also pass the actual value and never the string value.
const String strQuery3 = "INSERT INTO TServiceInstruments (sim, sid, sis, sih, sip, lid) VALUES (#sim, #sid, #sis, #sih, #sip, #lid)";
using(var conection = new SqlConnection(strConnString))
using(SqlCommand command = new SqlCommand(strQuery3, connection))
{
command.Parameters.Add(new SqlParameter("#sim", SqlDbType.VarChar, 200){Value = sim});
command.Parameters.Add(new SqlParameter("#sid", SqlDbType.VarChar, 200){Value = sid});
command.Parameters.Add(new SqlParameter("#sis", SqlDbType.VarChar, 200){Value = sis});
command.Parameters.Add(new SqlParameter("#sih", SqlDbType.VarChar, 200){Value = sih});
command.Parameters.Add(new SqlParameter("#sip", SqlDbType.Int){Value = sip});
command.Parameters.Add(new SqlParameter("#lid", SqlDbType.Int){Value = lid});
connection.Open();
command.ExecuteNonQuery();
}
Final note: You really need to learn how to read Exceptions and this includes the Stack Trace which points directly to the line in the call stack where the Exception originated. If you can understand this then debugging becomes much easier.

Maybe this doesn't deserve to be an answer, but I'm trying to build some reputation, so here goes :).
I suspect that your error lies in the "insert into TServiceInstruments ..." statement. Namely, you are giving the table more (or less) columns. As a good practice, always specify the columns, like this:
insert into TServiceInstruments (column1, column2, column3)
values (1, 2, 3)

Retain a value defined inside of a while statement

I'm trying to use the value assigned to the variable BinId outside of the while statement as below:
cmd.CommandText = "SELECT max(binID) from bin";
MySqlDataReader idReader = cmd.ExecuteReader();
int BinId;
while (idReader.Read())
{
BinId = idReader.GetInt32(0);
System.Diagnostics.Debug.WriteLine(BinId);
}
is there a way I can do this?
Edit: This is what I'm trying to do with BinId
cmd.CommandText = "insert into mydb1.missedbin values (null, '" + personIDdata + "','" + dateFound + "','"+ BinId +"')";

Change while to if. This is because you are only getting a single value so there is no need for a while, there will only ever be 1 record. You should also check the value of the resulting binId to ensure it is a positive number (which I assume would be the expected result if there is a record).
int BinId = 0;
cmd.CommandText = "SELECT max(binID) from bin";
// wrap your reader in a using block
using(MySqlDataReader idReader = cmd.ExecuteReader())
{
if (idReader.Read())
{
BinId = idReader.GetInt32(0);
System.Diagnostics.Debug.WriteLine(BinId);
}
if(BinId < 1)
return; // You did not get a value so exit your method or do something....
}
// NOTE: DO NOT DO THIS, always use parameterized queries
cmd.CommandText = "insert into mydb1.missedbin values (null, '" + personIDdata + "','" + dateFound + "','"+ BinId +"')";
About your insert statement, do not write queries like this ever. Always use parameterized queries.

Insert data to Mysql getting slower and slower

I need to insert 388 datas per minute to local Database.
At first when the table is Empty, I only need 5 second to Insert to database.
But when the table gets larger, the program efficacy slow down to more than one minute when the amount of rows comes to 1,026,558.
And the useage of CPU is 100%. It's unusual.
here is my code:
public static void dataToDB(String[] routeIDArray,String[] levelArray,String[] valueArray,String[] travelTimeArray, int amountOfData)
{
MySqlConnection con = new MySqlConnection(connStr);
MySqlCommand cmd = null;
MySqlDataReader rdr = null;
String sqlCmd, updateSqlCmd = "UPDATE `datetimetable` SET ";
for(int counter = 0; counter < amountOfData; counter++)
{
sqlCmd = "ALTER TABLE `datetimetable` ADD COLUMN IF NOT EXISTS `" + routeIDArray[counter] + "` INT NULL;"
+ "INSERT INTO `roadvalue`.`data` (`level`,`value`,`traveltime`) VALUES ("
+ levelArray[counter] + ","
+ valueArray[counter] + ","
+ travelTimeArray[counter] + ");"
+ "SELECT LAST_INSERT_ID() FROM `data`;";
cmd = new MySqlCommand(sqlCmd, con);
con.Open();
rdr = cmd.ExecuteReader();
rdr.Read();
updateSqlCmd += "`" + routeIDArray[counter] + "` = " + rdr[0] + ",";
rdr.Close();
}
updateSqlCmd = updateSqlCmd.TrimEnd(',');
updateSqlCmd += " WHERE EXISTS (SELECT * WHERE dateTime = '" + dateTime.ToString("yyyy-MM-dd HH:mm:00") + "');";
cmd = new MySqlCommand(updateSqlCmd, con);//update data key to datetimetable
cmd.ExecuteNonQuery();
Console.WriteLine("Done.");
con.Close();
}
public static void checkDateTimeExisted()
{
MySqlConnection con = new MySqlConnection(connStr);
MySqlCommand cmd;
String sqlCmd;
sqlCmd = "INSERT INTO `datetimetable` (`dateTime`) SELECT * FROM (SELECT '" + dateTime.ToString("yyyy-MM-dd HH:mm:00")
+ "') AS tmp WHERE NOT EXISTS(SELECT `dateTime` FROM `datetimetable` WHERE `dateTime` = '" + dateTime.ToString("yyyy-MM-dd HH:mm:00") + "') LIMIT 1; ";
con.Open();
cmd = new MySqlCommand(sqlCmd, con);
cmd.ExecuteNonQuery();
con.Close();
}
And Mysql Engine is InooDB, table "data" has one Auto_Increment Primary key, table "datetimetable" has an Auto_Increment Primary key and a not duplicate datetime as index.
What have I done wrong?

I find the answer, the command "SELECT LAST_INSERT_ID() FROM data;" should add LIMIT 1 or it will get all the ID kill the performance.

Do not use ALTER TABLE in a loop -- Plan ahead and provide all the columns before starting.
Do not use multiple statements in a single string. This has security implications, etc.
Do not use WHERE EXISTS... when (I think) a simple WHERE would work.
If there is UNIQUE(datetime), then the final INSERT can be simply
INSERT IGNORE INTO datetimetable
(datetime)
VALUE
('...');
Do batch inserts unless you need the LAST_INSERT_ID(). LIMIT 1 should not be necessary.
Do not 'Normalize' datetime values; it only slows things down. Just put the datetime as is in the main table.

ExecuteNonQuery CommandText property has not been initialized

When I click on this button, I face with this error:
executenonquery commandtext property has not been initialized
private void button_FirstStep_Click(object sender, EventArgs e)
{
SqlConnection Conn = new SqlConnection(Yahya.strcon);
Conn.Open();
int CurrentCount = Convert.ToInt32(label_CurrentCount.Text);
string strcom1 = "select * from vm1 where count = '" + (CurrentCount - 1) + "' and benchmarkid = '" + Structure.BenchmarkID + "' ";
SqlCommand cmd = new SqlCommand(strcom1, Conn);
SqlDataReader reader = cmd.ExecuteReader();
string strcom = "";
while (reader.Read())
{
if (reader["vmid"].ToString() != "")
{
string vmid = reader["vmid"].ToString();
strcom += "update vm1 set pmid = (select pmid from vm1 as VM2 where benchmarkid = '" + Structure.BenchmarkID + "' and vm2.count ='" + (CurrentCount - 1) + "' and vm2.vmid ='" + vmid + "' ) where count = '" + CurrentCount + "' and vmid = '" + vmid + "' and benchmarkid = '" + Structure.BenchmarkID + "' \n";
}
}//end of while
reader.Close();
cmd.CommandText = strcom;
cmd.ExecuteNonQuery();
}

Rene is quite right about his comment, looks like your reader.Read() returns false and that's why your code never goes into your while loop and your CommandText is assigned to "", that's why ExecuteNonQuery throws
ExecuteNonQuery: CommandText property has not been initialized
You can check your strcom is empty string or not to solve your problem but I see more wrong things in your code other than that..
Looks like your count column is numeric value but you supplied your CurrentCount - 1 as a character with single quotes. If it is not numeric, it should. Read: Bad habits to kick : choosing the wrong data type
Based on it's name, benchmarkid should(?) be numeric types as well.
You can solve this two problem with using parameterized queries because this kind of string concatenations are open for SQL Injection attacks.
Use using statement to dispose your connection, command and reader automatically instead of calling Close or Dispose methods manually.
Open your connection just before you execute your command.

You could solve this by simply debugging before asking.
The reason for this error is presumably that your first request returns zero results.
So reader.Read() is always false and strcom stays empty. You set an empty string as cmd.CommandText before the call to ExecuteNonQuery().
To solve this, simply check if the string is empty and execute the last query only if it is not empty:
...
reader.Close();
if (!string.IsNullOrEmpty(strcom))
{
cmd.CommandText = strcom;
cmd.ExecuteNonQuery();
}