accessing informix with ado.net

Accessing Informix With Accessing Informix With

ADO.NetADO.Net

Sean R. DuritySean R. DurityManager of ITManager of IT

CornerCap Investment CounselCornerCap Investment Counsel

Informix User Forum 2005 Moving Forward With Informix

Atlanta, Georgia December 8-9, 2005

AgendaAgenda

• The IBM Informix ADO.Net Driver• ADO.Net Driver Basics (with

examples)• Building Your Own Strongly Typed

Data Sets (with examples)• ADO.Net 2.0?• Limitations and Other Frameworks• Q & A

The Informix ADO.Net DriverThe Informix ADO.Net Driver• Current version is Client SDK 2.90TC1• Now installed by default, must have .Net

framework 1st• Namespace is IBM.Data.Informix - reference the

library IBM.Data.Informix.dll• Client SDK must be installed on any client that will

use the driver (not self-contained in the .dll)• Current documentation and examples are better

than the previous ones; reference guide twice as long

• Objects are similar to Microsoft’s Sql* objects, but use “Ifx” prefix (IfxConnection, IfxCommand, etc.)

The Informix ADO.Net DriverThe Informix ADO.Net Driver

• Installation Issues– If you have the older driver (2.81), you should

either install into the same directory or remove the previous installation first. I could not get the two versions to peacefully co-exist.

– There is a stored procedure creation script that must be run once against the sysmaster database (as user ‘informix’). Otherwise, features like the DataAdapter wizard won’t connect. Script is $INFORMIXDIR/etc/cdotnet.sql on any client machine.

The Informix ADO.Net DriverThe Informix ADO.Net Driver

• New features in 2.90– Adds an IfxDataAdapter Configure Data

Adapter wizard– Adds new types including IfxDateTime,

IfxDecimal, IfxBlob, and IfxClob– Supports IPv6 protocol

The Informix ADO.Net Driver The Informix ADO.Net Driver BasicsBasics

• Connection String (getting a connection)– Semi-colon delimited list of attributes put into the

ConnectionString property of the IfxConnection objectstring ConnectionString = "Host=" + HOST + "; " +

"Service=" + SERVICENUM + "; " +"Server=" + SERVER + "; " +"Database=" + DATABASE + "; " +"User Id=" + USER + "; " +"Password=" + PASSWORD + "; ";

IfxConnection conn = new IfxConnection();conn.ConnectionString = ConnectionString;try { conn.Open();} catch (IfxException ex) { }

BasicConnection.cs


• Executing an insert, update or deleteIfxCommand cmd = new IfxCommand("insert into test

values (1, 2, ‘ABC’)",bconn.conn);cmd.CommandTimeout = 200; //seconds allowed for

command to finishtry {

int rows = cmd.ExecuteNonQuery();}catch (IfxException ex) {

Console.WriteLine("Error "+ex.Message);}


• Iterating through a SELECT’s result set one-timeIfxCommand cmd = new IfxCommand("select * from

test",bconn.conn);try {

IfxDataReader dr = cmd.ExecuteReader();while (dr.Read()) {

int a = dr.GetInt32(0);int b = Convert.ToInt32(dr["b"]);string c = (String)dr[2];

}dr.Close();

}catch (IfxException ex) {

Console.WriteLine("Error "+ex.Message);}


• Executing a Stored Procedure with “in” parameterIfxCommand cmd = new

IfxCommand("test_proc",bconn.conn);cmd.CommandType = CommandType.StoredProcedure;

//from System.Datacmd.Parameters.Add("in_parameter",2); //many ways

to create thesetry {

cmd.ExecuteScalar();}catch (IfxException ifxe) {

Console.WriteLine("Error "+ifxe.Message);}

Building Your Own Strongly Building Your Own Strongly Typed DataSetsTyped DataSets

• The DataSet– Microsoft’s disconnected database object

– like an in-memory database– One or more DataTables

• Each DataTable has a DataAdapter that interacts with the actual data store

– Can have primary keys, relations, etc.– Derived from ComponentModel, so it is

available in the Designer as graphical object

DataSet DiagramDataSet Diagram


• Why Strongly Typed?– Intellisense for remembering and inserting table

and column names– Compiler catches table and column name errors– Property editors show table and column names

• Creating a Strongly Typed DataSet– Microsoft DataAdapter has Configure Data Adapter

and Generate DataSet wizards– Informix DataAdapter has just added Configure

Data Adapter. It has no Generate DataSet wizard.– More manual coding required to build strongly

typed DataSets for Informix


DataSetBuilderabstract classImplementsIBuildable

XxxBuilder

YyyBuilder

Dat

aLib

rary

Bui

lder

dsXxx (typedDataSet)

dsYyy (typedDataSet)

Xxx(add

IfxDataAdapters)

Yyy (addIfxDataAdapters)


• Built-in Tools– DataSet.WriteXmlSchema()– XSD schema file– XSD compiler (xsd.exe provided w/ .Net framework)

• Created Tools– DataSetBuilder and IBuildable interface

• Includes generalized CompileXSD() that executes the xsd.exe compiler

– XxxBuilder for each DataSet (inherits from DataSetBuilder)• Key method to override is BuildXSD()

– DataLibraryBuilder• Builds each IBuildable class that it finds


• Generates– A dsXxx strongly typed DataSet class

• Extending– Create an Xxx class that inherits from dsXxx– Insert all the IfxDataAdapters and commands

required to interact with the database– Xxx is a fully-contained data object

Examples With CodeExamples With Code

• Goal is code like this:Console.WriteLine(client.clientcode + “ “ +

client.clientacctname+ “ “ + client.createdate);

• Not this:

Console.WriteLine(ds.Tables[“clients”].Rows[ “clientcode”] + “ “ + ds.Tables[“clients”].Rows[ “clientacctname”] + “ “ + ds.Tables[“clients”].Rows [“createdate”] );


Clientstest table

create table 'infx'.clientstest ( clientcode SERIAL not null, clientacctname CHAR(60) not null, primarycontact CHAR(30) not null, primaddrcode CHAR(10), createdate DATE, initialamt DECIMAL(18,0))


IBuildable interface

public interface IBuildable {string FileName {get; set;}string FilePath {get; set;}Logger Log {get; set;}DataSet DS {get; set;}

void BuildXSD();

void CompileXSD(string outputDirectory);}


• Abstract DataSetBuilder class– Implements IBuildable – Has a concrete method for CompileXSD(), so

we only write it once– BuildXSD() is the virtual method– Also includes the property definitions– Is the parent for the concrete Builder classes

(which must override BuildXSD() )

DataSetBuilder.cs


• ClientsBuilder class– Concrete descendant of DataSetBuilder– Key method is the override of BuildXSD()– Manually build an untyped DataSet (tables,

keys, relations, etc.) then call the DataSet’s WriteXMLSchema() method

ClientsBuilder.cs


• DataLibraryBuilder class– WindowsForm application that uses reflection

to generate the .cs files for each DataSet– IMPORTANT: The BuilderAssembly must point

to the one in this project’s directory. Otherwise, reflection will think that the types do not match and nothing will get built

– If the DataSet in the Builder class changes, this must be re-run

DataLibraryBuilder.cs


• dsClients.xsd and dsClients.cs– Generated by the DataLibraryBuilder and

put into the directory for the DataLibrary project

– Our 42 line ClientsBuilder becomes a 43 line xsd file, which then generates a 500 line .cs file. That .cs file (dsClients.cs) is a strongly-typed DataSet. We will extend it for even more convenience.

dsClients.xsd dsClients.cs


• Extending to Clients.cs– Inherits from the strongly typed dsClients

DataSet– Includes IfxDataAdapters and their associated

commands for selecting, inserting, deleting, and updating

– Becomes the developer-friendly data object– The place where database-intensive

knowledge is required– Overrides Fill() and Update() from DataSet

Clients.cs


• Using Our Clients Object– There is a typed AddclientsRow() method on

the clients DataTable– There is a FindByclientcode() method on

the clients DataTable– Clients can be dragged onto Windows (or

Web) form and bound to controls– clientsRow has members named and typed

for each column (e.g., clientsRow.initialamt)

LibraryConsoleTest.cs

ADO.Net 2.0ADO.Net 2.0

• MicroSoft fixed some underlying problems with its DataSet implementation (indexing). For large DataSets it can provide an order of magnitude performance improvement.– Note: the current Informix driver has its own

performance problems marshaling data from unmanaged to managed code. This also impacts the performance of large DataSets.

• Driver Availability from IBM - No word.

Limitations and Other OptionsLimitations and Other Options

• Concurrency checking– Could be implemented with interface and concurrency column

• Data binding – can be flaky and not always bi-directional• No caching or lazy instantiation• Can’t make DataSets “global” and still use designer-aided

binding• No relations between objects• Null data can cause problems• Open source .Net ORM frameworks still emerging – no

Informix-specific implementations that I have found• However, for a very robust ORM and databinding

framework, look at DevForce from IdeaBlade. There is a Lite/free version for client server applications. (www.ideablade.com) It initially uses OLEDb and works with Informix.

http://www.ideablade.com/

Q&A/DiscussionQ&A/Discussion

• Other Resources– Code and article of this content at:

www.ibm.com/– ADO.Net Cookbook - Bill Hamilton– Microsoft ADO.Net - David Sceppa– DevForce framework

(www.ideablade.com)

Accessing Informix With Accessing Informix With ADO.NetADO.Net

Sean R. DuritySean R. [email protected]@cornercap.com

Informix User Forum 2005 Moving Forward With Informix

Atlanta, Georgia December 8-9, 2005

accessing informix with ado.net

Documents