I am a DBA and have decided as a project to help me learn c# / ef to build an app that monitors sql servers, the idea is to develop a windows service that runs to collect all the stats from various sql instances using scheduled jobs in .net quartz. i.e. connected users and details from various dynamic management views.
to store the configuration data i.e. what servers to monitor I am using an sql database so it just contains a table of servers to monitor you will be able to add move via a web ui.
now the issue I have is how to loop through the servers "table" in EF and obtain the connection strings column and use this to connect to the various sql instances to get stats. (these will later be written back to the database for analysis by a front end)
e.g.configuration table data:
servername: test server
connectionstring: testserver\inst1
hope that all makes sense, thanks for your time
You can create a list of all your connection string keys like this-
List<String> DataVaseKeys = new List<String>(); DataVaseKeys.Add("testserver\inst1");
DataVaseKeys.Add("testserver\inst2");
foreach (var key in DataVaseKeys) {
string currentConString=System.Configuration.ConfigurationManager.
ConnectionStrings[key].ConnectionString;
//access to the data base with your connection string here
}
Related
I am little stuck in using LINQ to insert one database table to another database table located on another server as a WCF Data Service.
Suppose I have an Item class on the local database and the same Item class on the the remote server, and I want to copy all the records across.
Is there a possibility to do this from: -
private Uri svcUri = new Uri("someurl/WcfDataService.svc");
Entities = new Entities(svcUri);
.....
I know that LINQ to SQL is mostly a 1-1 mapping between classes and the database, but I heard it is possible.
You just need to construct a connectionstring pointing at the right database. That database has to have the tables the EF expects to have though. (The code would look like yours, but I've never used a Uri for a connection string.)
However, it would be more efficient to do via a stored procedure on your source database, via a Linked Database to y=the Target. This because if you do it via WCF the data has to travel twice: SourceDB -> WCF service -> TargetDB, whereas with a SP it only has one hop: SourceDB -> TargetDB. Also in the SP it will operate pretty much as a set operation whereas the WCF service will have to process one row at a time.
EDIT - Apologies: I didn't notibe the MySQL tag. I don't know whether MySQL supports Linked Databases, so feel free to ignore this if it doesn't.
first hi all,
i got a db sqlite in my project also got xml files and i translate data from xml and save to local db,
string documentsPath = Environment.GetFolderPath(Environment.SpecialFolder.Personal);
string localFilename = "personel.xml";
string localPath = Path.Combine(documentsPath, localFilename);
this is my local db, im planing to move db3 to iss, when i move should i give
localpath like = 192.23.21.2/www/personel.xml?
or should i add more things like http://docs.xamarin.com/guides/cross-platform/application_fundamentals/web_services/ ?
and second question
what if multiple users update or delete from table?
there is a one db3 file and same time 3 connections how can i manage it?
SQLite is not designed to work as a multi-user database.
If you have many client programs accessing a common database over a
network, you should consider using a client/server database engine
instead of SQLite.
It is also a really bad idea to allow your mobile client app to talk directly to a remote database. This is why web services are usually recommended as an additional layer between your client and a central, remote database. They allow you to introduce an additional layer of control and security over your data access.
I created a windows forms application in C #, and a database MS SQL server 2008 Express, and I use LINQ-to-SQL query to insert and edit data.
The database is housed on a server with Windows Server 2008 R2 (standard edition). Right now I have the application running on five different computers, and users are authenticated through active directory.
One complaint reported to me was that sometimes when different data is entered and submitted, the same data do not appear in the listing that contains the application. I use try catch block to send the errors but errors do not appear in the application; but the data simply disappear.
The id of the table records is an integer auto-increment. As I have to tell them the registration number that was entered I use the following piece of code:
try{
ConectionDataContext db = new ConectionDataContext();
Table_Registers tr = new Table_Registers();
tr.Name=textbox1.text;
tr.sector=textbox2.text;
db.Table_Registers.InsertOnSubmit(tr);
db.SubmitChanges();
int numberRegister=tr.NumberRegister;
MessageBox.Show(tr.ToString());
}
catch{Exception e}
I wonder if I'm doing something wrong or if you know of any article on the web that speaks how to insert data from different clients in MSSQL Server databases, please let me know.
Thanks.
That's what a database server DOES: "insert data simultaneously from different clients".
One thing you can do is to consider "transactions":
http://www.sqlteam.com/article/introduction-to-transactions
Another thing you can (and should!) do is to insure as much work as possible is done on the server, by using "stored procedures":
http://www.sql-server-performance.com/2003/stored-procedures-basics/
You should also check the SQL Server error logs, especially for potential deadlocks. You can see these in your SSMS GUI, or in the "logs" directory under your SQL Server installation.
But the FIRST thing you need to do is to determine exactly what's going on. Since you've only got MSSQL Express (which is not a good choice for production use!), perhaps the easiest approach is to create a "log" table: insert an entry in your "log" every time you insert a row in the real table, and see if stuff is "missing" (i.e. you have more entires in the log table than the data table).
I'm making an app that will be installed and run on multiple computers, my target is to make an empty local database file that is installed with the app and when user uses the app his database to be filled with the data from the app .
can you provide me with the following examples :
what do I need to do so my app can connect to its local database
how to execute a query with variables from the app for example how would you add to the database the following thing
String abc = "ABC";
String BBB = "Something longer than abc";
and etc
Edit ::
I am using a "local database" created from " add > new item > Local database" so how would i connect to that ? Sorry for the dumb question .. i have never used databases in .net
Depending on the needs you could also consider Sql CE. I'm sure that if you specified the database you're thinking of using, or your requirements if you're usure you would get proper and real examples of connection strings etc.
Edit: Here's code for SqlCe / Sql Compact
public void ConnectListAndSaveSQLCompactExample()
{
// Create a connection to the file datafile.sdf in the program folder
string dbfile = new System.IO.FileInfo(System.Reflection.Assembly.GetExecutingAssembly().Location).DirectoryName + "\\datafile.sdf";
SqlCeConnection connection = new SqlCeConnection("datasource=" + dbfile);
// Read all rows from the table test_table into a dataset (note, the adapter automatically opens the connection)
SqlCeDataAdapter adapter = new SqlCeDataAdapter("select * from test_table", connection);
DataSet data = new DataSet();
adapter.Fill(data);
// Add a row to the test_table (assume that table consists of a text column)
data.Tables[0].Rows.Add(new object[] { "New row added by code" });
// Save data back to the databasefile
adapter.Update(data);
// Close
connection.Close();
}
Remember to add a reference to System.Data.SqlServerCe
I'm not seeing anybody suggesting SQL Compact; it's similar to SQLite in that it doesn't require installation and tailors to the low-end database. It grew out of SQL Mobile and as such has a small footprint and limited feature-set, but if you're familiar with Microsoft's SQL offerings it should have some familiarity.
SQL Express is another option, but be aware that it requires a standalone installation and is a bit beefier than you might need for an applciation's local cache. That said it's also quite a bit more powerful than SQL Compact or SQLite.
Seems like you're:
-Making a C# app that will be installed and run on multiple
computers
-That needs a local database (I'm assuming an RDBMS)
-You need to generate a blank database at installation
-You then need to be able to connect to the database and populate it when
the app runs.
In general, it seems that you need to read up on using a small database engine for applications. I'd start by checking out SQLite, especially if you need multi-OS capability (eg., your C# program will run on Microsoft's .NET Framework and Novell's Mono). There are C# wrappers for accessing the SQLite database.
I believe this question is about the "Local Database" item template in Visual Studio:
What are you considering as a database? From what little you've provided in your question, I'd suggest SQLite.
You can get sample code from their site Sqlite.NET
Not sure I fully understand what you're asking but Sqlite is a good option for lightweight, locally deployed database persistence. Have a look here:
http://www.sqlite.org/
and here for an ADO.NET provider..
http://sqlite.phxsoftware.com/
For 1)
The easiest way to provide this functionality is through SQL Server Express User Instances. SQL Server Express is free, so your user does not have to pay additional license for SQL Server, and the User Instance is file-based, which suits your requirement.
For 2)
This is a big topic. You may want to go through some of the tutorials from Microsoft to get the feeling of how to connect to DB, etc.
I have been working in a business writing advanced software apps, and obviously im provided with access to our SQL server and all the connection strings needed.This is fine for my job now - but what if i wanted to do this for a new (very small) business... If i wanted to purchase a small database server and set up a piece of software that talks to the databases on this server, how would i go about a) Talking and connecting to the server in code (c#) and b)What would i need regarding things like internet/phone connections etc to make this possible.
Edit: the reason it would need a server is because it would need to be accessed from 2 or 3 different computers in different locations?
Actually there are quite a few ways to create a database connection, but I would say one of the easiest ways is to utilize the methods and classes found in System.Data.SQLClient. A basic connection would look something like the following:
using System.Data.SQLClient;
namespace YourNamespace
{
public class DatabaseConnect
{
public DataType getData()
{
DataType dataObj = new DataType();
SqlConnection testConn = new SqlConnection("connection string here");
SqlCommand testCommand = new SqlCommand("select * from dataTable", testConn);
testConn.Open()
using (SqlDataReader reader = testCommand.ExecuteReader())
{
while (reader.Read())
{
//Get data from reader and set into DataType object
}
}
return dataObj;
}
}
}
Keep in mind, this is a very, very simple version of a connection for reading data, but it should give you an idea of what you need to do. Make sure to use a "using" or "try/catch" statement to ensure that the connection is closed and resources are freed after each use (whether it successfully gets data or not).
As for your other question about what equipment you may require. In the beginning I would suggest just creating the database on your local machine and running tests from there. Once you are confident with trading data back and forth, feel free to move the database to another box or an online server. Any internet connection type should suffice, though I can't vouch for dial-up, haven't used it in years.
One final note, if you do happen to decide to move to an online server system, make sure that the service you use allows for outside connections. Certain services use shared server systems, and force users to use their internal database interfaces to manage and write to the database.
--- EDIT ---
As for the server system itself, build up a separate box on your local network that you can see, and load up the database software of your choice. Since you are using C#, it would probably be easiest to go with Microsoft SQL Server 2005 / 2008. The installation is rather straightforward, and it will prompt you to automatically create your first database while installing.
After installation it will be up to you to add in the tables, stored procedures, custom functions, etc... Once your base structure is created, go ahead and use the above code to make some simple connections. Since you are familiar with the above practices then I'm sure you know that all you really need to do is target the server machine and database in the connection string to be on your way.
In case your application is small (by small I mean the usage of resources like CPU and memory) then your SQL Server can reside on the same box.
Else you need to have a separate server box for your database and connect to that from your application. In this case, preferably your database box and application box would be on the local area network.
Check this link for having a connection to SQL Server from C# code - http://www.codeproject.com/KB/database/sql_in_csharp.aspx
cheers
You should probably expose your database with an xml web services layer, so that your architecture will be scalable. The general idea is host your sql server and webservices, using Native SQL Server XML Web Services you can make this available to your remote clients. When in your clients you simply add a service reference in Visual Studio and your data will now be available in your client app.
Hope this helps some.
Cheers
You may find the connectionstrings website useful - worth bookmarking.