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Stored procedure doesn't return an int value

MySql Procedure Code:
CREATE DEFINER=`root`#`localhost` PROCEDURE `USP_CreateCliente`(IN nome_cliente VARCHAR(45))
BEGIN
Select 20;
INSERT INTO clienti ( nome_cliente )
VALUES ( nome_cliente );
Select id_cliente from clienti;
END
C# code in the controller page:
ClienteInfo CI = new ClienteInfo();
DboUser objdbo = new DboUser();
int id_cliente = 0;
CI.nome_cliente = txtNomeCliente.Text;
id_cliente = objdbo.CreateClienteInfo(CI);
DboUser class:
public int CreateClienteInfo(ClienteInfo CI)
{
int result;
MySqlConnection conn = new MySqlConnection();
DbConnection db = new DbConnection();
conn = db.ConnessioneDb();
MySqlCommand cmd = new MySqlCommand(Costanti.StoredProcedures.USP_CreateCliente, conn);
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddWithValue("#nome_cliente", CI.nome_cliente);
result = cmd.ExecuteNonQuery();
conn.Close();
return result;
}
I want my C# code to retrieve the id of my customer after inserting it into the database, so I can save it to the session and retrieve it again later in a page that will print a document with the customer's informations.
My id_cliente returns 0, do you notice any syntax error?
Did I do something wrong?
I'm 90% sure it's a problem dealing with the stored precedure tough, cause the customer is inserted correctly

Change this line
result = cmd.ExecuteNonQuery();
to
result = Convert.ToInt32(cmd.ExecuteScalar());
but you should also change your stored procedure because it doesn't return the last id generated for you by the AUTO_INCREMENT column id_cliente
CREATE DEFINER=`root`#`localhost` PROCEDURE `USP_CreateCliente`(IN nome_cliente VARCHAR(45))
BEGIN
INSERT INTO clienti ( nome_cliente ) VALUES ( nome_cliente );
Select LAST_INSERT_ID();
END
In MySql, to get the generated auto_increment value, you could use LAST_INSERT_ID(), next, your C# code don't need to use ExecuteNonQuery, which returns just the number of rows that you have changed, added or deleted, but you use ExecuteScalar which returns the first column of the first row of the last SELECT command executed by your stored procedure. (It is the SELECT LAST_INSERT_ID())
Also, to complete the answer, you don't really need a stored procedure for this kind of simple work. The advantages should be minimal while the problems related to a different piece of software to maintain are self evident.
Your C# code could be (removed the usage of your DbConnection class because it is not clear what it does)
public int CreateClienteInfo(ClienteInfo CI)
{
int result;
string cmdText = #"INSERT INTO clienti ( nome_cliente ) VALUES ( nome_cliente );
Select LAST_INSERT_ID();";
using(MySqlConnection conn = new MySqlConnection(....connectionstring .....))
using(MySqlCommand cmd = new MySqlCommand(cmdText, conn);
{
conn.Open()
cmd.Parameters.AddWithValue("#nome_cliente", CI.nome_cliente);
result = Convert.ToInt32(cmd.ExecuteScalar())
return result;
}
}
Here you use the possibility to pass batch commands to your MySql engine, meaning two commandtexts with the same MySqlCommand separating them with the semicolon

Getting primary key value of recently added record in SQL Server database

For the web app that I am working on, whenever a user adds a new record to the database, the system validates if the record has successfully been added or not:
if (txnHnd.AddNewTxnDetails(txnDetails) == true && txnHnd.AddNewTxnName(txnName) == true)
{
string message = "Record has been saved.";
lblErrorMsg.Text = message;
Response.Redirect("FXTxnList.aspx");
}
else
{
string message = "Saving record failed.";
lblErrorMsg.Text = message;
}
Now, IF the record has been successfully added, only then will the system insert a sort of Reference Number to the newly-added record. My table has a primary key called TxnID of type int. It's an auto-increment number BTW. The question is, how do I extract the TxnID of the newly added record from the database? I need to put the code inside the if part of the if-else statement, where it says that the Record has been saved.

Update/Create the SP like
CREATE PROC SP_Insert
(
#name VARCHAR(50),
#id INT OUTPUT
)
AS
INSERT INTO Table (ColumnName) VALUES (#name)
SET #id=SCOPE_IDENTITY()
and then call this sp from ado.net like below
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = "SP_Insert";
SqlParameter param = new SqlParameter();
param.Name = "#id";
param.Direction = ParameterDirection.Output;
cmd.Parameters.Add(param);
cmd.ExecuteNonQuery();
int id = (int)param.Value;

If you can modify the stored proc/command you use to insert a new record, you should use SCOPE_IDENTITY() to return the last generated identity value:
SELECT CAST(SCOPE_IDENTITY() AS INT)
If you're using a stored proc and cannot modify it, you need to use ##IDENTITY, as SCOPE_IDENTITY() works only in the same scope (in this case within a stored proc). Be careful though, as ##IDENTITY will return the last identity not limited by scope which can be affected e.g. by triggers.
SELECT CAST(##IDENTITY AS INT)
More on MSDN.

A better way to achieve INSERT without hitting the database multiple times

I have the following, I could make it work as I want to but I think i'm doing it the wrong way, could you please explain how this could be done in a more efficient way ? While also looping on Categories and doing the same as with Districts within the same Insert() Method.
Thanks in advance.
#region Methods
public int Insert(List<District> Districts, List<Category> Categories)
{
StringBuilder sqlString = new StringBuilder("INSERT INTO Stores (name, image) VALUES (#Name, #Image);");
using (SqlConnection sqlConnection = new
SqlConnection(ConfigurationManager.ConnectionStrings["OahuDB"].ConnectionString))
{
SqlCommand sqlCommand = new SqlCommand(sqlString.ToString(), sqlConnection);
sqlCommand.Parameters.AddWithValue("#Name", this.Name);
sqlCommand.Parameters.AddWithValue("#Image", this.Image);
sqlConnection.Open();
int x = (int)sqlCommand.ExecuteScalar();
sqlString.Clear();
sqlCommand.Parameters.Clear();
foreach (District item in Districts)
{
sqlString.AppendLine("INSERT INTO districts_has_stores (district_id, store_id) VALUES (#DistrictID, #StoreID);");
sqlCommand.CommandText = sqlString.ToString();
sqlCommand.Parameters.AddWithValue("#DistrictID", item.ID);
sqlCommand.ExecuteNonQuery();
}
return x;
}
}
EDIT
Is is wrong to achieve the above by doing the following ?
sqlString.Clear();
sqlCommand.Parameters.Clear();
sqlString.AppendLine("INSERT INTO districts_has_stores (district_id, store_id) VALUES (#DistrictID, #StoreID);");
sqlCommand.CommandText = sqlString.ToString();
sqlCommand.Parameters.AddWithValue("#StoreID", x);
foreach (District item in Districts)
{
sqlCommand.Parameters.AddWithValue("#DistrictID", item.ID);
sqlCommand.ExecuteNonQuery();
}
sqlString.Clear();
sqlCommand.Parameters.Clear();
sqlString.AppendLine("INSERT INTO categories_has_stores (category_id, store_id) VALUES (#CategoryID, #StoreID);");
sqlCommand.CommandText = sqlString.ToString();
sqlCommand.Parameters.AddWithValue("#StoreID", x);
foreach (Category item in Categories)
{
sqlCommand.Parameters.AddWithValue("#CategoryID", item.ID);
sqlCommand.ExecuteNonQuery();
}

The first obvious thing is to move the invariant part of the sqlCommand out of the loop
sqlCommand.Parameters.Clear();
sqlString.Clear();
sqlString.AppendLine("INSERT INTO districts_has_stores (district_id, store_id) VALUES (#DistrictID, #StoreID);");
sqlCommand.CommandText = sqlString.ToString();
sqlCommand.Parameters.AddWithValue("#DistrictID", 0); // as dummy value
sqlCommand.Parameters.AddWithValue("#StoreID", x); // invariant
foreach (District item in Districts)
{
sqlCommand.Parameters["#DistrictID"].Value = item.ID;
sqlCommand.ExecuteNonQuery();
}
But this doesn't answer your fundamental problem. How to avoid hitting the database multiple times.
You could build a query with multiple inserts like this
sqlString.Clear();
sqlString.Append("INSERT INTO districts_has_stores (district_id, store_id) VALUES (");
foreach(District item in Districts)
{
sqlString.Append(item.ID.ToString);
sqlString.Append(", ")
sqlString.Append(x.ToString());
sqlString.Append("),");
}
sqlString.Length--;
sqlCommand.CommandText = sqlString.ToString()
But string concatenation is really a bad practice and I present this solution just as an example and I don't want to suggest this kind of approach.
The last possibility are Table-Valued Parameters (Only from SqlServer 2008).
First you need to create a Sql Type for the table you will pass in
CREATE TYPE dbo.DistrictsType AS TABLE
( DistrictID int, StoreID int )
and a StoredProcedure that will insert the data from the datatable passed in
CREATE PROCEDURE usp_InsertDistricts
(#tvpNewDistricts dbo.DistrictsType READONLY)
AS
BEGIN
INSERT INTO dbo.Districts (DistrictID, StoreID)
SELECT dt.DistrictID, dt.StoreID FROM #tvpNewDistricts AS dt;
END
then, back to your code you pass the district into the storedprocedure
(Probably you need to convert your List in a DataTable)
DataTable dtDistricts = ConvertListToDataTable(Districts);
SqlCommand insertCommand = new SqlCommand("usp_InsertDistricts", sqlConnection);
SqlParameter p1 = insertCommand.Parameters.AddWithValue("#tvpNewDistricts", dtDistricts);
p1.SqlDbType = SqlDbType.Structured;
p1.TypeName = "dbo.DistrictsType";
insertCommand.ExecuteNonQuery();
Well, if you look back at the link above, you will find other ways to pass your data in a single step to the database backend.... (Scroll to the end and you will find also a method that doesn't require a stored procedure on the database)

Assuming Stores has an identity column, in SQL Server, create a table type and a table-valued parameter to take advantage of it:
CREATE TYPE dbo.DistrictsTVP AS TABLE
(
DistrictID INT -- PRIMARY KEY? I hope so.
);
GO
CREATE PROCEDURE dbo.InsertStoreAndDistricts
#Name NVARCHAR(255),
#Image <some data type???>,
#Districts dbo.DistrictsTVP READONLY
AS
BEGIN
SET NOCOUNT ON;
DECLARE #StoreID INT;
INSERT dbo.Stores(name, [image]) SELECT #Name, #Image;
SET #StoreID = SCOPE_IDENTITY();
INSERT dbo.district_has_stores(district_id, store_id)
SELECT DistrictID, #StoreID
FROM #Districts;
END
GO
Then in C#, you can pass your List in directly without any looping:
using (...)
{
SqlCommand cmd = new SqlCommand("dbo.InsertStoreAndDistricts", sqlConnection);
cmd.CommandType = CommandType.StoredProcedure;
SqlParameter tvparam = cmd.Parameters.AddWithValue("#Districts", Districts);
tvparam.SqlDbType    = SqlDbType.Structured;
// other params here - name and image
cmd.ExecuteNonQuery();
}

Recently in my project i used XML as a data type in my stored proc and did insert update and delete in just one shot instead of hitting the database multiple times .
Sample Stored proc
ALTER PROCEDURE [dbo].[insertStore]
#XMLDATA xml,
#name varchar(50),
#image datatype
AS
Begin
INSERT INTO Store
(name
,image
)
Select XMLDATA.item.value('#name[1]', 'varchar(10)') AS Name,
XMLDATA.item.value('#image[1]', 'yourData type') AS Image
FROM #XMLDATA.nodes('//Stores/InsertList/Store') AS XMLDATA(item)
END
Similarly you can write for update and delete .In C# u need to create the xml
public string GenerateXML(List<District> Districts)
var xml = new StringBuilder();
var insertxml = new StringBuilder();
xml.Append("<Stores>");
for (var i = 0; i < Districts.Count; i++)
{ var obj = Districts[i];
insertxml.Append("<Store");
insertxml.Append(" Name=\"" + obj.Name + "\" ");
insertxml.Append(" Image=\"" + obj.Image + "\" ");
insertxml.Append(" />");
}
xml.Append("<InsertList>");
xml.Append(insertxml.ToString());
xml.Append("</InsertList>");
SqlCommand cmd= new SqlCommand("insertStore",connectionString);
cmd.CommandType=CommandType.StoredProcedure;
SqlParameter param = new SqlParameter ();
param.ParameterName ="#XMLData";
param.value=xml;
paramter.Add(param);
cmd.ExecuteNonQuery();

Personally, I would create a stored procedure for the insert and pass in a Table-Valued param, which would allow you to do
INSERT tbl (f1, f2, ... fN)
SELECT * FROM #TVP
http://msdn.microsoft.com/en-us/library/bb510489.aspx
Unless you're using SQL 2005, then I would use an XML param in my stored proc and Serialize a collection to be inserted.

Think about your system design. Where is the data that you need to insert coming from? If it's already in the database, or another database, or some other kind of data store, you should be able to achieve a more bulk kind of transfer, simply inserting from one database to the other in a loop in stored procedure.
If the data is coming from a user, or some incompatible data store, like say an export from some third party program, then you basically have to realize that to get it into the database will involve quite of few round-trips to the database. You can use some tables, or XML or such , but those are actually closer to doing a bulk insert using other methods.
The bottom line is that SQL databases are designed to do inserts one at a time. This is 99% of the time OK because you are never asking users using the UI to type in thousands of things at one time.

How to return autoincrement value in insert query in SQLite?

In my project I use System.Data.SQLite. Database has table Tags, which contains autoincrement primary field ID (type Integer). When I write:
using (SQLiteCommand command = conn.CreateCommand())
{
command.CommandText = "insert into Tags(name) values(#name) returning into #id";
command.Parameters.Add("#id", DbType.Int32).Direction = ParameterDirection.Output;
command.ExecuteNonQuery();
}
Visual Studio said that the operation is not supported. How to fix it?
Error occurs on line:
command.Parameters.Add("#id", DbType.Int32).Direction = ParameterDirection.Output;

I found working query:
SELECT last_insert_rowid()

SQLite 3.35.0 and newer supports RETURNING clause:
The RETURNING clause is designed to provide the application with the values of columns that are filled in automatically by SQLite.
The code could look like:
INSERT INTO Tags(name) VALUES(#name) RETURNING ID;

I advice to use Stored Procedure.
IN SQL Server has ##IDENTITY system Variable . it returns the last autoincrement value
CREATE PROCEDURE SPGetLastAutoInc #name varchar, #lastAutoResult INT OUTPUT AS
INSERT INTO Tags(name) values(#name)
SET #lastAutoResult = ##IDENTITY
-- Return the number of all items ordered.
RETURN lastAutoResult
GO

How to insert a record and return the newly created ID using a single SqlCommand?

I'm using an SqlCommand object to insert a record into a table with an autogenerated primary key. How can I write the command text so that I get the newly created ID when I use the ExecuteScalar() method?

INSERT INTO YourTable(val1, val2, val3 ...)
VALUES(#val1, #val2, #val3...);
SELECT SCOPE_IDENTITY();
Don't forget the semicolons at the end of each statement.

Add the following line to the end of the Sql Query...
SELECT SCOPE_IDENTITY()
And then use the ExecuteScalar method on the SqlCommand object...
var rowCount = command.ExecuteScalar()

insert into Yourtable()
values()
SELECT SCOPE_IDENTITY()
I just ran a test and verified that the semi-colons are optional using SQL Server 2005 SP2, and .Net 3.5

Add an output parameter to the command object and then set the value to the new ID in the stored procedure.
Stored Procedure:
#ID AS INT OUTPUT
[Insert Command]
SET #ID = SCOPE_IDENTITY()
.NET:
cmd.CommandText = "stored_procedure";
SqlParameter pID = new SqlParameter("ID", DBType.Int32, 4);
pID.Direction = ParameterDirection.Output;
cmd.ExecuteScalar();
int id = Convert.ToInt32(cmd.Parameters["ID"].Value.ToString());

Don't use ##IDENTITY, however simple it may seem. It can return incorrect values.
SELECT SCOPE_IDENTITY()
appears to be the obvious choice.

Although I like Dave Markle's answer, ( and I see you did too, since you marked it as your answer ), that method can fail if you have triggers on your database, that audit CUD operations, and your audit table has an IDENTITY column. It would return the value of the Audit table's identity, not the table you just inserted into, since the audit table actualy happen after.
In that case, a more generic method can be used that will work in both cases, regardless of any auditing. Its a bit more wordy, but you get what you pay for.
example:
#"DECLARE #tmp AS TABLE ( id int )
INSERT INTO case
(
caseID,
partID,
serialNumber,
hardware,
software,
firmware
)
OUTPUT Inserted.ID into #tmp
VALUES
(
#caseID,
#partItemID,
#serialNumber,
#hardware,
#software,
#firmware
)
Select ID from #tmp" )

Immediately after your insert stmt, use
SELECT CAST(scope_identity() AS bigint) ---- incase you have a return result as int64
This will return the column created id/identity.

If your id is a Guid, then I found this solution to be best:
INSERT INTO YourTable (val1, val2, val3)
OUTPUT inserted.id
VALUES (#val1, #val2, #val3)
Thanks #Scott Ivey
Full demo:
internal static Guid InsertNote(Note note)
{
Guid id;
using (
var connection =
new SqlConnection(ConfigurationManager.ConnectionStrings["dbconn"].ConnectionString))
{
connection.Open();
using (
var command =
new SqlCommand(
"INSERT INTO Notes ([Title],[Text]) " +
"OUTPUT inserted.id " +
$"VALUES ('{title}','{text}');", connection))
{
command.CommandType = CommandType.Text;
var reader = command.ExecuteReader();
reader.Read();
id = reader.GetGuid(reader.GetOrdinal("id"));
}
connection.Close();
}
return id;
}
I would recommend using a Stored Procedure, but this is for unit testing our repository.

Straight out of the Whirlpool:
If you're using MS SQL you can use "SELECT ##IDENTITY as Value" after your insert to get the last ID generated
and:
##IDENTITY and SCOPE_IDENTITY return the last identity value generated in any table in the current session. However, SCOPE_IDENTITY returns the value only within the current scope; ##IDENTITY is not limited to a specific scope.
Edit: As pointed out in the comments, you should always use SCOPE_IDENTITY, not ##IDENTITY.