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: http://itpm.msu.su/mysql/Manual_chapter/manual_ODBC.html
Дата изменения: Tue Feb 15 06:19:57 2000 Дата индексирования: Mon Oct 1 21:54:12 2012 Кодировка: |
MySQL provides support for ODBC by means of the MyODBC program.
MyODBC is a 32-bit ODBC (2.50) level 0 driver for connecting a ODBC-aware application to MySQL. MyODBC works on Windows95, Windows98, NT and on most Unix platforms.
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.
MyODBC is in public domain and you can find the newest version at http://www.mysql.com/download_myodbc.html.
If you want to install MyODBC on a Unix box, you will also need an ODBC manager. MyODBC is known to work both with most of the Unix ODBC managers. You can find a list at these in the ODBC-related links section on the MySQL useful links page. See section 1.9 Useful MySQL-related links.
On Windows/NT 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, one can in this case install new ODBC drivers with Microsoft's ODBC setup program :( The solution to this is to reboot your computer in 'safe mod' (You can choose this by pressing F8 just before your machine start windows during rebooting), install MyODBC and reboot to normal mode.
GRANT
command. See section 7.26 GRANT
and REVOKE
syntax.
Notice that there are other configuration options in the screen of MySQL (trace, don't prompt on connect, etc) that you can try if you run into problems.
There are three possibilities for specifying the server name on Windows95:
ip hostnameFor example:
194.216.84.21 my_hostname
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 20.4.37 mysql_options()
.
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 mail myodbc@lists.mysql.com about this!
Most programs should work with MyODBC, but for each of those listed below, we have tested it ourselves or gotten confirmation from some user that it works:
BLOB
columns as OLE OBJECTS
. If
you want to have MEMO
columns instead, you should change the
column to TEXT
with ALTER TABLE
.
DATE
columns properly. If you have a problem
with these, change the columns to DATETIME
.
"Query|SQLSpecific|Pass-Through"
from the Access menu.
Active
or use the
method Open
. Note that Active
will start by automaticly issue
a SELECT * FROM ...
query that may not be a good thing if your tables
are big!
VARCHAR
rather than ENUM
, as
it exports the latter in a manner that causes MySQL grief.
CONCAT()
function. For example:
select CONCAT(rise_time), CONCAT(set_time) from sunrise_sunset;Values retrieved as strings this way should be correctly recognized 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.
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);
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');
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;
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,
tag the `Trace MyODBC' option flag in the MyODBC
connect/configure screen. The log will be written to file
`C:\myodbc.log'. Note that you must use MYSQL.DLL
and not
MYSQL2.DLL
for this option to work!
Check the queries that MyODBC sends to the MySQL server; You
should be able to find this 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@lists.mysql.com. 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 to make a archive (tar or zip) that contains a MyODBC log file, the ODBC log file and a README file that explains the problem. You can send this to ftp://www.mysql.com/pub/mysql/secret. Only we at TCX 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 a 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!
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