I'm creating a rptlibrary to share with all the reports in my company.
The library has an oda datasource created and shared to all reports. We want to do some querys from ReportEventAdapter.initialize() to the database to get information from the database. I can acces the datasource in the library in this way:
ReportDesignHandle rdh = (ReportDesignHandle)reportContext.getReportRunnable().getDesignHandle();
DesignSessionImpl ds = rdh.getModule().getSession();
String rsf = ds.getResourceFolder( );
LibraryHandle libhan = ds.openLibrary(rsf + "/my.rptlibrary" ).handle( );
DataSourceHandle datasource = libhan.findDataSource("myDS");
But once I have the datasource, there's no way to get a connection to the database from the datasource. The only way to do this, is creating a classic JDBC connection to the database using the data from the datasource? Is there any way to use a more elegant method to connect to the database from the java handler? Like using pooling, reusing the connection, etc..
Thanks.
We can iterate over dataset values in a report script event, thus if a dataset is defined with a JNDI URL, queries can take advantage of a connection pool.
However it is quite complicated. There is a full example in this topic: the script defined in "getDefaultValueList" event of the report parameter can be moved anywhere in the report and then initialize a global variable. In particular we could move it to "initialize" event, or to "beforeFactory" event (in your case "beforeFactory" is probably what you want).
Related
I am having issues attempting to connect to two different databases in one Qt Application. I have my information database that stores all the information collected by the application and the new Log database which allows me to track all the changes that occur to the Application, button presses, screen loads etc, for easy debugging after its release. Separately, the databases work perfectly, but when I try to use both of them, only one will work. I read that this could be because I wasn't naming the connections and obviously only the most recently connected database could use the default connection. However when I give the databases names they wont work at all, isOpen() will return true on both, but as soon as they attempt to execute a query I get the errors
"QSqlQuery::prepare: database not open"
"QSqlError(-1, "Driver not loaded", "Driver not loaded")"
My two database declarations are:
database_location = filepath.append("/logger.sqlite");
logDB = QSqlDatabase::addDatabase("QSQLITE", "LoggerDatabaseConnection");
logDB.setHostName("localhost");
logDB.setDatabaseName(database_location);
for the Logger Database connection and :
database_location = filepath.append("/db.sqlite");
db = QSqlDatabase::addDatabase("QSQLITE", "NormalDB");
db.setHostName("localhost");
db.setDatabaseName(database_location);
Also when I am running the first query on the databases to see if their tables exist I am using
QSqlQuery query("LoggerDatabaseConnection");
and likewise for the normal database, but I am still getting connection issues even after declaring the database connection to run the query on.
The database used for the application is declared as a static QSqlDatabase in a namespace to create a global effect, so everyone can access it, that was a previous programmer, and I created the Log database as Singleton with a private database connection. Like I said both versions of the code work separately but when they are together they are fighting each other. I know there is a huge debate over the proper design of Singleton vs Dependecy Injection, but again the code works separately so I am happy with how it is designed for now. If there is any missing information or if you have any ideas, please let me know. Thank you.
QSqlQuery query("LoggerDatabaseConnection");
The first parameter of the constructor is the query, not the connection name. It will use the default connection since you specified no database object.
Try something like this:
QSqlQuery query1("YourFirstQuery", db);
QSqlQuery query2("YourSecondQuery", logDB);
Important: Also do not forget to open and close the database before / after using it by calls to QSqlDatabase::open() and QSqlDatabase::close().
The correct way to have multiple databases is to not use the pointer returned from the static addConnection method. You should use the connectionName argument:
https://doc.qt.io/qt-5/qsqldatabase.html#addDatabase-1 during initilization and query usage:
example:
void MyClass::initDb(QString dbPath, QString connName)
{
// initial db usage, etc
QSqlDatabase db = QSqlDatabase::addDatabase(YOUR_DRIVER, connName);
db.setDatabaseName(dbPath);
// open it, etc
}
void MyClass::updateThing(QString val, QString name, QString connName)
{
QString q = QString("UPDATE THINGS SET val=%1 WHERE name=%2").arg(val, name);
// add the reference to your database via the connection name
QSqlDatabase db = QSqlDatabase::database(connName);
QSqlQuery query(db);
query.exec(q);
// handle the query normally, etc
}
I'm using Yii Framework to create my project. I need to export some data from MySQL (my project) to an external Microsoft SQL server which is on the same network.
Basically, the user needs to click on a button (which will do the export-insert) in my view and the results should be displayed - Success (if the query has been successful) or Failure (if something went wrong).
The results part is quite easy as I'll be using 'setFlash' to display the appropriate message but I want to know how to insert data into an external database through Yii.
Do you have any idea how this can be done?
Well, I agree with #SuVeRa on the first part of defining two db instances in the config.php but i don't think the sql Commands part is necessary (Plus i hate writing sql :D )
Instead you can do:
class SomeModel extends CActiveRecord
{
...
// Override the getDbConnection() function to use the ms sql db connection
public function getDbConnection()
{
return Yii::app()->ms_sql_db_connection; // The name of the connection in config.php
}
public function transfer()
{
// Here you can do all the transferring logic using normal Yii Active Record functions
}
}
Check out the docs on getDbConnection().
I have a ReportViewer control in a WindowsFormsHost tag in my WPF application. When I use this code:
rptViewer1.LocalReport.ReportPath = ...
List<ReportParameter> parms = new List<ReportParameter>();
parms.Add(new ReportParameter("regionID", "01"));
rptViewer1.LocalReport.SetParameters(parms);
rptViewer1.RefreshReport();
I get an error about a data source instance not being supplied. I can run the stored procedure manually and then use it to populate a datasource object, like...
var dt = DAL.GetData()
var rds = new ReportDataSource("DataSet1", dt);
rptViewer1.LocalReport.DataSources.Add(rds);
And this will cause the report to display, but then I am passing in my parameters to the GetData() method rather than to the report; this doesn't seem right. In my SSRS project, I am using a shared datasource, and it allows me to pass in the parameters on the report front end as I would expect. What am I doing wrong?
If you are using ProcessingMode = Local, then YOU are responsible for large portions of teh report. You or your application defined which parameters there are, how data is loaded, & what sub-report or drill through events do. You must explicitly code these. If the ProcessingMode = Remote, then all of these elements are handled by the reporting server. Microsoft doesn't spell this out very clearly in MSDN, but I can see their justification being "if you are going to host the report in your app, then you can be responsible for all the details".
I have a WinForms project, which consists of 10 forms. Forms are called to each other, each shape is drawn to the database
(I'm using LINQ to SQL) how best to create a database connection, I set up the connection when loading the main form
string path = "Data Source = | DataDirectory | \ \ Database.sdf";
Database db = new Database (path);
and then loading each window is transmitted through an object constructor db, then work with the database,
Window1 win1 = new Window1(db)
there may be a better way?
Try to use static class for your db operations.
Well for one, you should abstract your database logic / connections into their own class or assembly. The connection string shouldn't be hard coded, but come from the app.config file.
I don't think you should be passing around the connection object.
As I stated above, abstract our your database code and wrap your the context in a Using statement.
I've searched the stackoverflow for a long time and didn't find a solution fit my situation, so I asked here.
I have a single asp.net website, and need the web app to access different SQL Server database by the subdomain name.
According to the url request subdomian to determine the access the different database.
prj1.test.com prj1--->use the prj1_DB
prj2.test.com prj2 use the prj2_DB
I couldn't find a better practice to solve the issue.
My intuition solution:
when the url request coming, get the url subdomain, get the subdomain's db connection string stored in the main db, passing the connection string to the DAL to get the data.
Index.aspx.cs
DataTable dt = ProjectObject.GetProjectIndexNotice(new object[] { 0, CurrentProject.DbConnectionString });
ProjectObject.cs
public static DataTable GetProjectIndexNotice(object[] param)
{
ProjectDLC obj = new ProjectDLC();
return obj.GetProjectIndexNotice(param);
}
ProjectDAL.cs
public DataTable GetProjectIndexNotice(object[] param)
{
return base.GetDataTableFromDatabase(param, "NEMP_GetProjectIndexNotice");
}
DALBase.cs
DataBase db = new Microsoft.Practices.EnterpriseLibrary.Data.Sql.SqlDatabase(CurrentProject.DbConnectionString);
I want to find a better way to solve this problem.
The solution I using above is:
get the dbConnectionString from main DB,
passing it over the Index.page ->BusinessObject Layer -->DAL Layer
It's so bad that passing the DB connection string from UI page to the DAL layer.
Any ideas?
Update 1:
What I really want is: don't pass the db connection string from UI to DAL layer.
I want to find a solution that don't do pass the db connstr from UI to DAL linearly.
Is there some pattern in asp.net to share some variable for UI layer and DAL Layer?
Update 2:
if I stored the project db info in a xml file or in the main db, it looks like this
it's a key-value part for the project. here is the question, I get the values all in the main DB or a xml file. How I get the key when I need to access the DB in DAL layer?
in the DAL layer, how to get the correct key for the currnet url request?
it's back to the above, pass the key from UI to DAL. that's I want to avoid.
the real problem is, I can get the key from url request in the UI layer, and I can get the value for that key in the DAL layer. but there is a gap between the two layers, How to conquer this gap?
If you can compute your connection string from a base connection string, then you could do something like this:
store the base connection string in your web.config
<connectionStrings>
<add name="BaseConnString"
connectionString="server=MyServer;database=master;Integrated Security=SSPI;" />
</connectionStrings>
load the base connection string into a SqlConnectionStringBuilder in your code:
string baseConnStr = WebConfigurationManager.ConnectionString["BaseConnString"].ConnectionString;
SqlConnectionStringBuilder scsBuilder =
new SqlConnectionStringBuilder(baseConnStr);
now, just define the database you want to connect to, e.g. based on something in your URL
scsBuilder.InitialCatalog = "ProjectDatabase" + ........ ;
use the resulting complete connection string for your SqlConnection:
using(SqlConnection _con = new SqlConnection(scsBuilder.ConnectionString))
{
// do something
}
Check out the MSDN docs on SqlConnectionStringBuilder.
With this approach, you'd store a single "base" connection string in your web.config and this wouldn't be changing, and using SqlConnectionStringBuilder, you can safely and efficiently define and "compute" your real, "dynamic" connection strings at runtime.
How about adding add the connection strings in web.config as:
Subdomain_connectionString
Now read the subdomain from Request:
Reading connection string from web.config in your DL:
ConfigurationManager.ConnectionStrings[Subdomain_connectionString].ConnectionString
Update:
You can also use xml files to store connection string values:
<ROOT>
<Project_1>
<IPAddress></IPAddress>
<DBName></DBName>
...
</Project_1>
<Project_2>
....
</ROOT>
Anytime a new project is added/removed this xml file would be updated. Use XPath expressions to parse the xml file.
#Passing Connection string from UI to DAL: Just try to add the System.web namespace to DAL layer. This would give access to Request object in DAL. Now you can get the subdomain and build the connectionstring in DAL itself. Not sure whether this is a right approach, but might work in your case.