I am creating a C# WinForms Application along with SQL LocalDB. I am new to SQL and I am following this tutorial (timestamp: 5.50) to add database in project. I have also added a setup project to install the application to other PCs. When I installed the project for the first time it worked perfectly well, but when I updated the database schema (added one more column) the changes are not reflecting, updated version of setup & assembly and installed the setup file again, the database schema changes are not reflecting in the application. It is giving the following error:
My code is something like this:
private void load_list()
{
string conn = Properties.Settings.Default.dbAgeConnectionString;
SqlConnection sqlConn = new SqlConnection(conn);
string sqltext = "SELECT Name, Age, DOB from Users";
if (sqlConn.State != ConnectionState.Open) sqlConn.Open();
DataTable table = new DataTable();
SqlDataAdapter adapter = new SqlDataAdapter(sqltext,sqlConn);
adapter.Fill(table);
sqlConn.Close();
lstRecords.DisplayMember = "Name";
lstRecords.ValueMember = "Id";
lstRecords.DataSource = table;
gvrecords.DataSource = table;
}
Connection String:
Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=|DataDirectory|\dbAge.mdf;Integrated Security=True
I tried adding the database files manually in Application folder of Setup but still no results.
I searched on the internet but did not find any database version control or upgrade method for SQL LocalDB. Is there any way I can achieve this?
Thanks in advance.
I am trying to use the new Microsoft.Data.SqlClient in my .Net Core application. Whenever I select a column that has a datatype of Geography, I get the following error.
Unable to cast object of type 'Microsoft.SqlServer.Types.SqlGeography' to type 'Microsoft.Data.SqlClient.Server.IBinarySerialize'.'
To reproduce, I created a database on my computer (SQL2019) with one table:
DROP TABLE IF EXISTS geotest
GO
CREATE TABLE geotest (g GEOGRAPHY)
GO
INSERT INTO geotest (g)
VALUES
( 0xe6100000010cec51b81e854b4040ec51b81e852b58c0 ),
( 0xe6100000010c6666666666a64740713d0ad7a3905ec0 )
I create a console application project (Visual Studio 2019, .Net Core 3.1) and add the NUGET package: Microsoft.Data.SqlClient
Here is my sample app:
using System;
using Microsoft.Data.SqlClient;
namespace TestWithOtherSQL
{
class Program
{
static void Main(string[] args)
{
SqlConnection conn = new SqlConnection("Data Source=localhost;Initial Catalog=joe;Trusted_Connection=True;");
conn.Open();
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
cmd.CommandType = System.Data.CommandType.Text;
cmd.CommandText = #"SELECT g FROM geotest";
SqlDataReader sr = cmd.ExecuteReader();
while (sr.Read())
{
var a = sr[0];
}
conn.Close();
Console.WriteLine("Hello World!");
}
}
}
It throws the error on this line:
var a = sr[0];
Unable to cast object of type 'Microsoft.SqlServer.Types.SqlGeography' to type 'Microsoft.Data.SqlClient.Server.IBinarySerialize'.'
Troubleshooting:
If I change out the Nuget package to System.Data.SqlClient and include package Microsoft.SqlServer.Types (change the using to System.Data.SqlClient) The same code works.
So why don't I just do that? Good question... My actual database is on Azure SQL DB and I need to use Microsoft.Data.SqlClient to support ActiveDirectory Password Authentication (that does not work with System.Data.SqlClient) - but that's a different issue....
Also Microsoft.Data.SqlClient is the "new" ".NetCore" way of doing things. Not a huge issue for me right now, but not sure if that would work if we ported to Linux are tried to run in an Azure function.
I have a connection string in my config files like so
add name="entities" connectionString="Data Source=localhost;user id=username;password=somepassword;persist security info=True;database=dbname" providerName="MySql.Data.MySqlClient"
This works with localhost.
As soon as I change the Data Source to Data Source=123.34.45.56 <-- some remote server
I get MySql.Data.MySqlClient.MySqlException: Table 'mydb.Emails' doesn't exist
If I use connection code in c# it will work against the remote server : Example below
MySql.Data.MySqlClient.MySqlConnection mySqlConnection = new
MySql.Data.MySqlClient.MySqlConnection();
mySqlConnection.ConnectionString = "Data Source=123.34.45.56;user id=username;password=somepassword;persist security info=True;database=dbname";
string conString = mySqlConnection.ConnectionString;
using (MySqlConnection connection = new MySqlConnection(conString)) {
connection.Open();
using (MySqlCommand command = new MySqlCommand(
"SELECT * FROM emails",
connection)) {
using (MySqlDataReader reader = command.ExecuteReader()) {
while (reader.Read()) {
for (int i = 0; i < reader.FieldCount; i++) {
var tr = reader.GetValue(i);
}
}
}
}
}
How come the connection string in the web.config is throwing this error for every table MySql.Data.MySqlClient.MySqlException: Table 'mydb.Emails'doesn't exist.
The tables are there as the c# connection code can open a connection and query the data just fine.
How do I get the connection string to work?
John Garrard was correct. It was a case sensitivity issue with the database located on two different operating systems. I needed to make my entities case sensitive and the switching the connection string will work between the Windows development machine and the Linux production machine. Thanks.
I came across this issue when moving from a Windows dev to AWS test system. There is a parameter called "lower_case_table_names" that controls how MySql matches table names which defaults to 0 on linux and 1 in Windows (meaning case sensitive and insensitive):
On your AWS Console go to the RDS page.
Click on Parameter Groups.
Either create your own or click into the default parameter group.
Search for the parameter lower_case_table_names.
Edit the value and set it to 1
Save the parameters and restart the db instance.
I am new to SmartDeviceProject. So When i try to connect MySQL to my project, MissingManifestResourceException through in Connection.open in below code?.
string connectionString = "server=192.168.1.100;database=mcubic;User Name=mcubic;Password=mcs#2011$;";
string query = "select b.Outlet_Master_Name from mcs_user_outlet a,outlet_master b where a.Mcs_User_Outlet_User_Id=3 and a.Mcs_User_Outlet_Outlet_Id = b.Outlet_Master_Id";
MySqlConnection connection = new MySqlConnection(connectionString);
MySqlCommand command = new MySqlCommand(query, connection);
connection.Open();
MySqlDataReader Reader = command.ExecuteReader();
while (Reader.Read())
{
comboBox1.Items.Add(Reader[0].ToString());
}
connection.Close();
How do i solve this,. I am imported MySql.Data.CF.dll for this project.
Via Krish Kapadia from MSDN forums:
Solution :
MySql's version 5.2.7.0 is the stable version. I use dll of this version. Other versions have many problems. so first I download dll of that version from mysql site.
here is the link :
http://dev.mysql.com/downloads/connector/net/5.2.html
I have inserted one entry in 'mysql.user' table in which hostname will be '%' (means any user can connect to mysql). If you don't want to insert entry with hostname then you have to insert for all ip addresses who should be allowed to connect to mysql.
After inserting entry in 'mysql.user', I restarted MySQL service.
And then trying to connect to mysql and Connected....
source:
http://social.msdn.microsoft.com/Forums/eu/netfxcompact/thread/66f6386a-9963-4c2f-8d39-1c507a26a6c7
I've done this before in C++ by including sqlite.h but is there a similarly easy way in C#?
I'm with, Bruce. I AM using http://system.data.sqlite.org/ with great success as well. Here's a simple class example that I created:
using System;
using System.Text;
using System.Data;
using System.Data.SQLite;
namespace MySqlLite
{
class DataClass
{
private SQLiteConnection sqlite;
public DataClass()
{
//This part killed me in the beginning. I was specifying "DataSource"
//instead of "Data Source"
sqlite = new SQLiteConnection("Data Source=/path/to/file.db");
}
public DataTable selectQuery(string query)
{
SQLiteDataAdapter ad;
DataTable dt = new DataTable();
try
{
SQLiteCommand cmd;
sqlite.Open(); //Initiate connection to the db
cmd = sqlite.CreateCommand();
cmd.CommandText = query; //set the passed query
ad = new SQLiteDataAdapter(cmd);
ad.Fill(dt); //fill the datasource
}
catch(SQLiteException ex)
{
//Add your exception code here.
}
sqlite.Close();
return dt;
}
}
There is also an NuGet package: System.Data.SQLite available.
Microsoft.Data.Sqlite by Microsoft has over 9000 downloads every day, so I think you are safe using that one.
Example usage from the documentation:
using (var connection = new SqliteConnection("Data Source=hello.db"))
{
connection.Open();
var command = connection.CreateCommand();
command.CommandText =
#"
SELECT name
FROM user
WHERE id = $id
";
command.Parameters.AddWithValue("$id", id);
using (var reader = command.ExecuteReader())
{
while (reader.Read())
{
var name = reader.GetString(0);
Console.WriteLine($"Hello, {name}!");
}
}
}
I've used this with great success:
http://system.data.sqlite.org/
Free with no restrictions.
(Note from review: Original site no longer exists. The above link has a link pointing the the 404 site and has all the info of the original)
--Bruce
There is a list of Sqlite wrappers for .Net at http://www.sqlite.org/cvstrac/wiki?p=SqliteWrappers. From what I've heard http://sqlite.phxsoftware.com/ is quite good. This particular one lets you access Sqlite through ADO.Net just like any other database.
There's also now this option: http://code.google.com/p/csharp-sqlite/ - a complete port of SQLite to C#.
https://github.com/praeclarum/sqlite-net is now probably the best option.
Another way of using SQLite database in NET Framework is to use Fluent-NHibernate.
[It is NET module which wraps around NHibernate (ORM module - Object Relational Mapping) and allows to configure NHibernate programmatically (without XML files) with the fluent pattern.]
Here is the brief 'Getting started' description how to do this in C# step by step:
https://github.com/jagregory/fluent-nhibernate/wiki/Getting-started
It includes a source code as an Visual Studio project.
Here I am trying to help you do the job step by step: (this may be the answer to other questions)
Go to this address , down the page you can see something like "List of Release Packages". Based on your system and .net framework version choose the right one for you. for example if your want to use .NET Framework 4.6 on a 64-bit Windows, choose this version and download it.
Then install the file somewhere on your hard drive, just like any other software.
Open Visual studio and your project. Then in solution explorer, right-click on "References" and choose "add Reference...".
Click the browse button and choose where you install the previous file and go to .../bin/System.Data.SQLite.dll and click add and then OK buttons.
that is pretty much it. now you can use SQLite in your project.
to use it in your project on the code level you may use this below example code:
make a connection string:
string connectionString = #"URI=file:{the location of your sqlite database}";
establish a sqlite connection:
SQLiteConnection theConnection = new SQLiteConnection(connectionString );
open the connection:
theConnection.Open();
create a sqlite command:
SQLiteCommand cmd = new SQLiteCommand(theConnection);
Make a command text, or better said your SQLite statement:
cmd.CommandText = "INSERT INTO table_name(col1, col2) VALUES(val1, val2)";
Execute the command
cmd.ExecuteNonQuery();
that is it.
Mono comes with a wrapper, use theirs!
https://github.com/mono/mono/tree/master/mcs/class/Mono.Data.Sqlite/Mono.Data.Sqlite_2.0 gives code to wrap the actual SQLite dll ( http://www.sqlite.org/sqlite-shell-win32-x86-3071300.zip found on the download page http://www.sqlite.org/download.html/ ) in a .net friendly way. It works on Linux or Windows.
This seems the thinnest of all worlds, minimizing your dependence on third party libraries. If I had to do this project from scratch, this is the way I would do it.
if you have any problem with the library you can use Microsoft.Data.Sqlite;
public static DataTable GetData(string connectionString, string query)
{
DataTable dt = new DataTable();
Microsoft.Data.Sqlite.SqliteConnection connection;
Microsoft.Data.Sqlite.SqliteCommand command;
connection = new Microsoft.Data.Sqlite.SqliteConnection("Data Source= YOU_PATH_BD.sqlite");
try
{
connection.Open();
command = new Microsoft.Data.Sqlite.SqliteCommand(query, connection);
dt.Load(command.ExecuteReader());
connection.Close();
}
catch
{
}
return dt;
}
you can add NuGet Package Microsoft.Data.Sqlite