Differences between .NET Providers

IBM Informix .NET Provider

The IBM Informix .NET Provider, sometimes referred to as the Client SDK .NET provider, works with only the Informix database server and internally uses the SQLI protocol to communicate with Informix.

IBM Data Server .NET Provider

The IBM Data Server .NET Provider, sometimes referred to as the Common .NET provider, is the next generation of the .NET provider for application development. This .NET provider includes a number of capabilities, especially in the area of web application development, making it the preferred .NET provider for new client development.

Comparison of supported features

There are several major differences between the features that are supported by the IBM Informix .NET provider and the IBM Data Server .NET Provider. Many of the features that are supported by the IBM Data Server .NET Provider are not supported by the IBM Informix .NET Provider.

The following table shows these differences:

Unsupported keywords in the ConnectionString property

Connection pooling settings

In the IBM Informix .NET Provider, the Connection Lifetime attribute specifies how long a connection can remain open.

In the IBM Data Server .NET Provider, the Connection Lifetime attribute specifies the number of seconds that the connection can remain open and idle in the pool.

Server keyword in the ConnectionString property

In the IBM Informix .NET Provider, the SERVER keyword should be used to specify the INFORMIXSERVER name as setup in the SetNet utility.

In theIBM Data Server .NET Provider, the SERVER keyword should be specified in the format <hostname>:<port_number>, where <hostname> is the machine name of the instance and <port_number> is the port on which the instance is listening.

Database keyword in the ConnectionString property

With the IBM Informix .NET Provider, you can connect to a server without specifying a database. With the IBM Data Server .NET Provider, database is a mandatory attribute.

The IBM Informix .NET Provider allows specifying the value for the Database attribute in the format dbname@server. The IBM Data Server .NET Provider does not support this format.

String values in quotation marks in the ConnectionString property

The IBM Informix .NET Provider supports database, server, and password keyword values in quotation marks.

Applications that use the IBM Data Server .NET Provider can specify values in quotation marks for the database and password keywords only when specifying an alias for a catalog connection.

IfxConnection.ServerType property

For this property, the IBM Informix .NET Provider returns the value Informix. The IBM Data Server .NET Provider returns the value that is received from the database server to which it is connected. For example, the provider connected to an Informix database server installed on a UNIX 64-bit system might return IDS/UNIX64.

Unsupported data types in SQL statements

The IBM Data Server .NET Provider does not allow access to the LIST, MULTISET, SET, or ROW data types because the Informix DRDA server does not support these types.

With the IBM Informix .NET Provider, you can select and return the values from the LIST, MULTISET, and ROW data types.

BYTE and TEXT data types

The IBM Data Server .NET Provider maps both Byte and BLOB data types to the IfxBlob data type. When binding an IfxBlob object as a parameter, applications must use the ::byte clause after the parameter marker. This clause indicates that the IfxBlob value corresponds to a byte column. Without the ::byte clause, a conversion error is returned.

DB2Parameter clobParam;

clobParam.IfxType = IfxType.Clob;
...
cmd.CommandText = "CALL textSP(?::text)";
---
cmd.ExecuteNonQuery();

Supported data types

The following table compares the more unusual Informix data types and how each .NET provider supports those data types.

Comparing classes and structures

The following table compares the differences between the .NET provider support for the data type classes and structures support.

Stored procedure differences

With the IBM Informix .NET Provider applications can read the return value of a stored procedure or function as a ReturnValue parameter.

With the IBM Data Server .NET Provider applications by default can read the return value of a stored procedure or function as a data reader. To read it as a ReturnValue parameter, applications must set the ResultSetAsReturnValue parameter to true in the IfxCommand or IfxConnection object. To read it is a ReturnValue parameter, applications must set the ResultSetAsReturnValue property to true in the IfxCommand or IfxConnection object.

IfxCommand.ExecuteScalar() method

Cmd.CommandText = "SELECT COUNT(*) FROM Tab";

IfxDataReader.GetString() method

The IBM Data Server .NET Provider does not allow the IfxDataReader.GetString() method if the underlying value is null. A null value results in an InvalidCast exception. This behavior is in contrast to the IBM Informix .NET Provider, which allows a null value and returns an empty string.

Error messages

Some error messages that are received by the IBM Data Server .NET Provider might differ from the messages received by the IBM Informix .NET Provider. For example, the IBM Informix .NET Provider has tags such as [Informix .NET provider] in the error messages. The IBM Data Server .NET Provider has just [IBM] in the error messages. Additionally, the error codes might be different for the same type of error.