Opening a database connection v8.0.2.1
An EDBConnection
object is responsible for handling the communication between an instance of EDB Postgres Advanced Server and a .NET application. Before you can access data stored in an EDB Postgres Advanced Server database, you must create and open an EDBConnection
object.
Creating an EDBConnection object
You can open a connection using one of the following approaches. In either case, you must import the namespace EnterpriseDB.EDBClient
.
Connection with a data source
Create an instance of the
EDBDataSource
object using a connection string as a parameter to the create method of theEDBDataSource
class.To open a connection, call the
OpenConnection
method of theEDBDataSource
object.
This example shows how to open a connection using a data source:
Connection without a data source
Create an instance of the
EDBConnection
object using a connection string as a parameter to the constructor of theEDBConnection
class.Call the
Open
method of theEDBConnection
object to open the connection.
This example shows how to open a connection without a data source:
Note
For EnterpriseDB.EDBClient 7.0.4
and later, we recommend EDBDataSource
to connect to EDB Postgres Advanced Server database or execute SQL directly against it. For more information on the data source, see the Npgsql documentation.
Connection string parameters
A valid connection string specifies location and authentication information for an EDB Postgres Advanced Server instance. You must provide the connection string before opening the connection. A connection string must contain:
- The name or IP address of the server
- The name of the EDB Postgres Advanced Server database
- The name of an EDB Postgres Advanced Server user
- The password associated with that user
You can include the following parameters in the connection string:
CommandTimeout
CommandTimeout
specifies the length of time (in seconds) to wait for a command to finish executing before throwing an exception. The default value is 20
.
ConnectionLifeTime
Use ConnectionLifeTime
to specify the length of time (in seconds) to wait before closing unused connections in the pool. The default value is 15
.
Database
Use the Database
parameter to specify the name of the database for the application to connect to. The default is the name of the connecting user.
Encoding
The Encoding
parameter is obsolete. The parameter always returns the string unicode
and silently ignores attempts to set it.
Integrated Security
Specify a value of true
to use Windows Integrated Security. By default, Integrated Security
is set to false
, and Windows Integrated Security is disabled.
Load Role Based Tables
Use Load Role Based Tables
to load table OIDs based on role. This change affects only the loading of table type OID and not the composite type. Setting this parameter to true
triggers the new functionality. The default value is false
.
MaxPoolSize
MaxPoolSize
instructs EDBConnection
to dispose of pooled connections when the pool exceeds the specified number of connections. The default value is 20
.
MinPoolSize
MinPoolSize
instructs EDBConnection
to preallocate the specified number of connections with the server. The default value is 1
.
Password
When using clear text authentication, specify the password to use to establish a connection with the server.
Pooling
Specify a value of false
to disable connection pooling. By default, Pooling
is set to true
to enable connection pooling.
No Reset On Close
When Pooling
is enabled and the connection is closed, reopened, and the underlying connection is reused, then some operations are executed to discard the previous connection resources. You can override this behavior by enabling No Reset On Close
.
Port
The Port
parameter specifies the port for the application to connect to.
Protocol
The specific protocol version to use (instead of automatic). Specify an integer value of 2
or 3
.
SearchPath
Use the SearchPath
parameter to change the search path to named and public schemas.
Server
The name or IP address of the EDB Postgres Advanced Server host.
SSL
Specify a value of true
to attempt a secure connection. By default, SSL
is set to false
.
sslmode
Use sslmode
to specify an SSL connection control preference. sslmode
can be:
prefer
— Use SSL if possible.require
— Throw an exception if an SSL connection can't be established.allow
— Connect without SSL. This parameter isn't supported.disable
— Don't attempt an SSL connection. This is the default behavior.
SyncNotification
Use the SyncNotification
parameter to specify for EDBDataprovider
to use synchronous notifications. The default value is false
.
Timeout
Timeout
specifies the length of time (in seconds) to wait for an open connection. The default value is 15
.
User Id
The User Id
parameter specifies the user name to use for the connection.
Example: Opening a database connection using ASP.NET
This example shows how to open a connection to an instance of EDB Postgres Advanced Server and then close the connection. The connection is established using the credentials specified in the DB_CONN_STRING
configuration parameter. See Using the .Net Connector for an introduction to connection information. Also see Connection string parameters for connection parameters.
If the connection is successful, a message appears indicating that the connection opened successfully.
Example: Opening a database connection from a console application
This example opens a connection with an EDB Postgres Advanced Server database using a console-based application.
Before writing the code for the console application, create an app.config
file that stores the connection string to the database. Using a configuration file makes it convenient to update the connection string if the information changes.
Enter the following code sample into a file:
Save the file as EDBConnection-Sample.cs
and compile it with the following command:
Compiling the sample generates a Console.exe
file. You can execute the sample code by entering Console.exe
. When executed, the console verifies that it opened successfully.
Example: Opening a database connection from a Windows form application
This example opens a database connection using a .NET WinForm application. To use the example, save the following code as WinForm-Example.cs
in a directory that contains the library files:
Change the database connection string to point to the database that you want to connect to. Then compile the file with the following command:
This command generates a WinForm.exe
file in the same folder that the executable was compiled under. Invoking the executable displays a message that the connection was successful.