9.2 MySQL ODBC Support

MySQL provides support for ODBC by means of the MyODBC program. This chapter will teach you how to install MyODBC, and how to use it. Here, you will also find a list of common programs that are known to work with MyODBC.

9.2.1 How To Install MyODBC

MyODBC 2.50 is a 32-bit ODBC 2.50 specification level 0 (with level 1 and level 2 features) driver for connecting an ODBC-aware application to MySQL. MyODBC works on Windows 9x/Me/NT/2000/XP and most Unix platforms. MyODBC 3.51 is an enhanced version with ODBC 3.5x specification level 1 (complete core API + level 2 features).

MyODBC is Open Source, and you can find the newest version at http://www.mysql.com/downloads/api-myodbc.html. Please note that the 2.50.x versions are LGPL licensed, whereas the 3.51.x versions are GPL licensed.

If you have problem with MyODBC and your program also works with OLEDB, you should try the OLEDB driver.

Normally you only need to install MyODBC on Windows machines. You only need MyODBC for Unix if you have a program like ColdFusion that is running on the Unix machine and uses ODBC to connect to the databases.

If you want to install MyODBC on a Unix box, you will also need an ODBC manager. MyODBC is known to work with most of the Unix ODBC managers.

To install MyODBC on Windows, you should download the appropriate MyODBC `.zip' file, unpack it with WinZIP or some similar program, and execute the `SETUP.EXE' file.

On Windows/NT/XP you may get the following error when trying to install MyODBC:

An error occurred while copying C:\WINDOWS\SYSTEM\MFC30.DLL. Restart
Windows and try installing again (before running any applications which
use ODBC)

The problem in this case is that some other program is using ODBC and because of how Windows is designed, you may not in this case be able to install a new ODBC drivers with Microsoft's ODBC setup program. In most cases you can continue by just pressing Ignore to copy the rest of the MyODBC files and the final installation should still work. If this doesn't work, the solution is to reboot your computer in "safe mode" (Choose this by pressing F8 just before your machine starts Windows during rebooting), install MyODBC, and reboot to normal mode.

• To make a connection to a Unix box from a Windows box, with an ODBC application (one that doesn't support MySQL natively), you must first install MyODBC on the Windows machine.
• The user and Windows machine must have the access privileges to the MySQL server on the Unix machine. This is set up with the GRANT command. See section GRANT.
• You must create an ODBC DSN entry as follows:
  • - Open the Control Panel on the Windows machine.
  • - Double-click the ODBC Data Sources 32-bit icon.
  • - Click the tab User DSN.
  • - Click the button Add.
  • - Select MySQL in the screen Create New Data Source and click the Finish button.
  • - The MySQL Driver default configuration screen is shown. See section How to Fill in the Various Fields in the ODBC Administrator Program.
• Now start your application and select the ODBC driver with the DSN you specified in the ODBC administrator.

Notice that there are other configuration options on the screen of MySQL (trace, don't prompt on connect, etc) that you can try if you run into problems.

9.2.2 How to Fill in the Various Fields in the ODBC Administrator Program

There are three possibilities for specifying the server name on Windows95:

• Use the IP address of the server.
• Add a file `\windows\lmhosts' with the following information:

  ip hostname

  For example:

  194.216.84.21 my_hostname

• Configure the PC to use DNS.

Example of how to fill in the ODBC setup:

Windows DSN name:   test
Description:        This is my test database
MySql Database:     test
Server:             194.216.84.21
User:               monty
Password:           my_password
Port:

The value for the Windows DSN name field is any name that is unique in your Windows ODBC setup.

You don't have to specify values for the Server, User, Password, or Port fields in the ODBC setup screen. However, if you do, the values will be used as the defaults later when you attempt to make a connection. You have the option of changing the values at that time.

If the port number is not given, the default port (3306) is used.

If you specify the option Read options from C:\my.cnf, the groups client and odbc will be read from the `C:\my.cnf' file. You can use all options that are usable by mysql_options(). See section mysql_options().

9.2.3 Connect parameters for MyODBC

One can specify the following parameters for MyODBC on the [Servername] section of an `ODBC.INI' file or through the InConnectionString argument in the SQLDriverConnect() call.

The option argument is used to tell MyODBC that the client isn't 100% ODBC compliant. On Windows, one normally sets the option flag by toggling the different options on the connection screen but one can also set this in the option argument. The following options are listed in the same order as they appear in the MyODBC connect screen:

If you want to have many options, you should add the above flags! For example setting option to 12 (4+8) gives you debugging without package limits!

The default `MYODBC.DLL' is compiled for optimal performance. If you want to debug MyODBC (for example to enable tracing), you should instead use `MYODBCD.DLL'. To install this file, copy `MYODBCD.DLL' over the installed `MYODBC.DLL' file.

9.2.4 How to Report Problems with MyODBC

MyODBC has been tested with Access, Admndemo.exe, C++-Builder, Borland Builder 4, Centura Team Developer (formerly Gupta SQL/Windows), ColdFusion (on Solaris and NT with svc pack 5), Crystal Reports, DataJunction, Delphi, ERwin, Excel, iHTML, FileMaker Pro, FoxPro, Notes 4.5/4.6, SBSS, Perl DBD-ODBC, Paradox, Powerbuilder, Powerdesigner 32 bit, VC++, and Visual Basic.

If you know of any other applications that work with MyODBC, please send mail to the myodbc mailing list about this! See section The MySQL Mailing Lists.

With some programs you may get an error like: Another user has modifies the record that you have modified. In most cases this can be solved by doing one of the following things:

• Add a primary key for the table if there isn't one already.
• Add a timestamp column if there isn't one already.
• Only use double float fields. Some programs may fail when they compare single floats.

If the above doesn't help, you should do a MyODBC trace file and try to figure out why things go wrong.

9.2.5 Programs Known to Work with MyODBC

Most programs should work with MyODBC, but for each of those listed here, we have tested it ourselves or received confirmation from some user that it works:

Program

Comment

Access

To make Access work:

• If you are using Access 2000, you should get and install the newest (version 2.6 or above) Microsoft MDAC (Microsoft Data Access Components) from http://www.microsoft.com/data/. This will fix the following bug in Access: when you export data to MySQL, the table and column names aren't specified. Another way to around this bug is to upgrade to MyODBC Version 2.50.33 and MySQL Version 3.23.x, which together provide a workaround for this bug!

  You should also get and apply the Microsoft Jet 4.0 Service Pack 5 (SP5) which can be found here http://support.microsoft.com/support/kb/articles/Q 239/1/14.ASP. This will fix some cases where columns are marked as #deleted# in Access.

  Note that if you are using MySQL Version 3.22, you must to apply the MDAC patch and use MyODBC 2.50.32 or 2.50.34 and above to go around this problem.

• For all Access versions, you should enable the MyODBC option flag Return matching rows. For Access 2.0, you should additionally enable Simulate ODBC 1.0.
• You should have a timestamp in all tables you want to be able to update. For maximum portability TIMESTAMP(14) or simple TIMESTAMP is recommended instead of other TIMESTAMP(X) variations.
• You should have a primary key in the table. If not, new or updated rows may show up as #DELETED#.
• Only use DOUBLE float fields. Access fails when comparing with single floats. The symptom usually is that new or updated rows may show up as #DELETED# or that you can't find or update rows.
• If you are linking a table through MyODBC, which has BIGINT as one of the column, then the results will be displayed as #DELETED. The work around solution is:
  • Have one more dummy column with TIMESTAMP as the datatype, preferably TIMESTAMP(14).
  • Check the 'Change BIGINT columns to INT' in connection options dialog in ODBC DSN Administrator
  • Delete the table link from access and re-create it.

  It still displays the previous records as #DELETED#, but newly added/updated records will be displayed properly.

• If you still get the error Another user has changed your data after adding a TIMESTAMP column, the following trick may help you:

  Don't use table data sheet view. Create instead a form with the fields you want, and use that form data sheet view. You should set the DefaultValue property for the TIMESTAMP column to NOW(). It may be a good idea to hide the TIMESTAMP column from view so your users are not confused.

• In some cases, Access may generate illegal SQL queries that MySQL can't understand. You can fix this by selecting "Query|SQLSpecific|Pass-Through" from the Access menu.
• Access on NT will report BLOB columns as OLE OBJECTS. If you want to have MEMO columns instead, you should change the column to TEXT with ALTER TABLE.
• Access can't always handle DATE columns properly. If you have a problem with these, change the columns to DATETIME.
• If you have in Access a column defined as BYTE, Access will try to export this as TINYINT instead of TINYINT UNSIGNED. This will give you problems if you have values > 127 in the column!

ADO

When you are coding with the ADO API and MyODBC you need to put attention in some default properties that aren't supported by the MySQL server. For example, using the CursorLocation Property as adUseServer will return for the RecordCount Property a result of -1. To have the right value, you need to set this property to adUseClient, like is showing in the VB code here:

Dim myconn As New ADODB.Connection Dim myrs As New Recordset Dim mySQL As String Dim myrows As Long myconn.Open "DSN=MyODBCsample" mySQL = "SELECT * from user" myrs.Source = mySQL Set myrs.ActiveConnection = myconn myrs.CursorLocation = adUseClient myrs.Open myrows = myrs.RecordCount myrs.Close myconn.Close

Another workaround is to use a SELECT COUNT(*) statement for a similar query to get the correct row count.

Active server pages (ASP)

You should use the option flag Return matching rows.

BDE applications

To get these to work, you should set the option flags Don't optimize column widths and Return matching rows.

Borland Builder 4

When you start a query you can use the property Active or use the method Open. Note that Active will start by automatically issuing a SELECT * FROM ... query that may not be a good thing if your tables are big!

ColdFusion (On Unix)

The following information is taken from the ColdFusion documentation:

Use the following information to configure ColdFusion Server for Linux to use the unixODBC driver with MyODBC for MySQL data sources. Allaire has verified that MyODBC Version 2.50.26 works with MySQL Version 3.22.27 and ColdFusion for Linux. (Any newer version should also work.) You can download MyODBC at http://www.mysql.com/downloads/api-myodbc.html

ColdFusion Version 4.5.1 allows you to us the ColdFusion Administrator to add the MySQL data source. However, the driver is not included with ColdFusion Version 4.5.1. Before the MySQL driver will appear in the ODBC datasources drop-down list, you must build and copy the MyODBC driver to `/opt/coldfusion/lib/libmyodbc.so'.

The Contrib directory contains the program `mydsn-xxx.zip' which allows you to build and remove the DSN registry file for the MyODBC driver on Coldfusion applications.

DataJunction

You have to change it to output VARCHAR rather than ENUM, as it exports the latter in a manner that causes MySQL grief.

Excel

Works. A few tips:

• If you have problems with dates, try to select them as strings using the CONCAT() function. For example:

  select CONCAT(rise_time), CONCAT(set_time) from sunrise_sunset;

  Values retrieved as strings this way should be correctly recognised as time values by Excel97.

  The purpose of CONCAT() in this example is to fool ODBC into thinking the column is of "string type". Without the CONCAT(), ODBC knows the column is of time type, and Excel does not understand that.

  Note that this is a bug in Excel, because it automatically converts a string to a time. This would be great if the source was a text file, but is plain stupid when the source is an ODBC connection that reports exact types for each column.

Word

To retrieve data from MySQL to Word/Excel documents, you need to use the MyODBC driver and the Add-in Microsoft Query help.

For example, create a db with a table containing 2 columns of text:

• Insert rows using the mysql client command-line tool.
• Create a DSN file using the ODBC manager, for example, `my' for the db above.
• Open the Word application.
• Create a blank new documentation.
• Using the tool bar called Database, press the button insert database.
• Press the button Get Data.
• At the right hand of the screen Get Data, press the button Ms Query.
• In the Ms Query create a New Data Source using the DSN file my.
• Select the new query.
• Select the columns that you want.
• Make a filter if you want.
• Make a Sort if you want.
• Select Return Data to Microsoft Word.
• Click Finish.
• Click Insert data and select the records.
• Click OK and you see the rows in your Word document.

odbcadmin

Test program for ODBC.

Delphi

You must use BDE Version 3.2 or newer. Set the Don't optimize column width option field when connecting to MySQL.

Also, here is some potentially useful Delphi code that sets up both an ODBC entry and a BDE entry for MyODBC (the BDE entry requires a BDE Alias Editor that is free at a Delphi Super Page near you. (Thanks to Bryan Brunton bryan@flesherfab.com for this):

fReg:= TRegistry.Create; fReg.OpenKey('\Software\ODBC\ODBC.INI\DocumentsFab', True); fReg.WriteString('Database', 'Documents'); fReg.WriteString('Description', ' '); fReg.WriteString('Driver', 'C:\WINNT\System32\myodbc.dll'); fReg.WriteString('Flag', '1'); fReg.WriteString('Password', ''); fReg.WriteString('Port', ' '); fReg.WriteString('Server', 'xmark'); fReg.WriteString('User', 'winuser'); fReg.OpenKey('\Software\ODBC\ODBC.INI\ODBC Data Sources', True); fReg.WriteString('DocumentsFab', 'MySQL'); fReg.CloseKey; fReg.Free; Memo1.Lines.Add('DATABASE NAME='); Memo1.Lines.Add('USER NAME='); Memo1.Lines.Add('ODBC DSN=DocumentsFab'); Memo1.Lines.Add('OPEN MODE=READ/WRITE'); Memo1.Lines.Add('BATCH COUNT=200'); Memo1.Lines.Add('LANGDRIVER='); Memo1.Lines.Add('MAX ROWS=-1'); Memo1.Lines.Add('SCHEMA CACHE DIR='); Memo1.Lines.Add('SCHEMA CACHE SIZE=8'); Memo1.Lines.Add('SCHEMA CACHE TIME=-1'); Memo1.Lines.Add('SQLPASSTHRU MODE=SHARED AUTOCOMMIT'); Memo1.Lines.Add('SQLQRYMODE='); Memo1.Lines.Add('ENABLE SCHEMA CACHE=FALSE'); Memo1.Lines.Add('ENABLE BCD=FALSE'); Memo1.Lines.Add('ROWSET SIZE=20'); Memo1.Lines.Add('BLOBS TO CACHE=64'); Memo1.Lines.Add('BLOB SIZE=32'); AliasEditor.Add('DocumentsFab','MySQL',Memo1.Lines);

C++ Builder

Tested with BDE Version 3.0. The only known problem is that when the table schema changes, query fields are not updated. BDE, however, does not seem to recognise primary keys, only the index PRIMARY, though this has not been a problem.

Vision

You should use the option flag Return matching rows.

Visual Basic

To be able to update a table, you must define a primary key for the table.

Visual Basic with ADO can't handle big integers. This means that some queries like SHOW PROCESSLIST will not work properly. The fix is to set the option OPTION=16384 in the ODBC connect string or to set the Change BIGINT columns to INT option in the MyODBC connect screen. You may also want to set the Return matching rows option.

VisualInterDev

If you get the error [Microsoft][ODBC Driver Manager] Driver does not support this parameter the reason may be that you have a BIGINT in your result. Try setting the Change BIGINT columns to INT option in the MyODBC connect screen.

Visual Objects

You should use the option flag Don't optimize column widths.

9.2.6 How to Get the Value of an AUTO_INCREMENT Column in ODBC

A common problem is how to get the value of an automatically generated ID from an INSERT. With ODBC, you can do something like this (assuming that auto is an AUTO_INCREMENT field):

INSERT INTO foo (auto,text) VALUES(NULL,'text');
SELECT LAST_INSERT_ID();

Or, if you are just going to insert the ID into another table, you can do this:

INSERT INTO foo (auto,text) VALUES(NULL,'text');
INSERT INTO foo2 (id,text) VALUES(LAST_INSERT_ID(),'text');

See section How Can I Get the Unique ID for the Last Inserted Row?.

For the benefit of some ODBC applications (at least Delphi and Access), the following query can be used to find a newly inserted row:

SELECT * FROM tbl_name WHERE auto IS NULL;

9.2.7 Reporting Problems with MyODBC

If you encounter difficulties with MyODBC, you should start by making a log file from the ODBC manager (the log you get when requesting logs from ODBCADMIN) and a MyODBC log.

To get a MyODBC log, you need to do the following:

1. Ensure that you are using `myodbcd.dll' and not `myodbc.dll'. The easiest way to do this is to get `myodbcd.dll' from the MyODBC distribution and copy it over the `myodbc.dll', which is probably in your `C:\windows\system32' or `C:\winnt\system32' directory.

   Note that you probably want to restore the old myodbc.dll file when you have finished testing, as this is a lot faster than `myodbcd.dll'.

2. Tag the `Trace MyODBC' option flag in the MyODBC connect/configure screen. The log will be written to file `C:\myodbc.log'.

   If the trace option is not remembered when you are going back to the above screen, it means that you are not using the myodbcd.dll driver (see the item above).

3. Start your application and try to get it to fail.

Check the MyODBC trace file, to find out what could be wrong. You should be able to find out the issued queries by searching after the string >mysql_real_query in the `myodbc.log' file.

You should also try duplicating the queries in the mysql monitor or admndemo to find out if the error is MyODBC or MySQL.

If you find out something is wrong, please only send the relevant rows (max 40 rows) to the myodbc mailing list. See section The MySQL Mailing Lists. Please never send the whole MyODBC or ODBC log file!

If you are unable to find out what's wrong, the last option is to make an archive (tar or zip) that contains a MyODBC trace file, the ODBC log file, and a README file that explains the problem. You can send this to ftp://support.mysql.com/pub/mysql/secret/. Only we at MySQL AB will have access to the files you upload, and we will be very discrete with the data!

If you can create a program that also shows this problem, please upload this too!

If the program works with some other SQL server, you should make an ODBC log file where you do exactly the same thing in the other SQL server.

Remember that the more information you can supply to us, the more likely it is that we can fix the problem!

Hosting by: Hurra Communications Ltd.
Generated: 2007-01-26 17:58:46