[+/-]
Most programs should work with Connector/ODBC, but for each of those listed here, there are specific notes and tips to improve or enhance the way you work with Connector/ODBC and these applications.
With all applications you should ensure that you are using the latest Connector/ODBC drivers, ODBC Manager and any supporting libraries and interfaces used by your application. For example, on Windows, using the latest version of Microsoft Data Access Components (MDAC) will improve the compatibility with ODBC in general, and with the Connector/ODBC driver.
[+/-]
The majority of Microsoft applications have been tested with Connector/ODBC, including Microsoft Office, Microsoft Access and the various programming languages supported within ASP and Microsoft Visual Studio.
If you have problem with Connector/ODBC and your program also works with OLEDB, you should try the OLEDB driver.
To improve the integration between Microsoft Access and MySQL through Connector/ODBC:
For all versions of Access, you should enable the
Connector/ODBC Return matching rows
option. For Access 2.0, you should additionally enable
the Simulate ODBC 1.0
option.
You should have a TIMESTAMP
column in
all tables that you want to be able to update. For
maximum portability, don't use a length specification in
the column declaration (which is unsupported within
MySQL in versions earlier than 4.1).
You should have a primary key in each MySQL table you
want to use with Access. If not, new or updated rows may
show up as #DELETED#
.
Use only DOUBLE
float fields. Access
fails when comparing with single-precision 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 using Connector/ODBC to link to a table that
has a BIGINT
column, the results are
displayed as #DELETED#
. The work
around solution is:
Have one more dummy column with
TIMESTAMP
as the data type.
Select the Change BIGINT columns to
INT
option in the connection dialog in
ODBC DSN Administrator.
Delete the table link from Access and re-create it.
Old records may still display as
#DELETED#
, but newly added/updated
records are 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 a table
data sheet view.
Instead, create 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 SQL statements that
MySQL can't understand. You can fix this by selecting
"Query|SQLSpecific|Pass-Through"
from
the Access menu.
On Windows NT, Access reports BLOB
columns as OLE OBJECTS
. If you want
to have MEMO
columns instead, you
should change BLOB
columns to
TEXT
with ALTER
TABLE
.
Access can't always handle the MySQL
DATE
column properly. If you have a
problem with these, change the columns to
DATETIME
.
If you have in Access a column defined as
BYTE
, Access tries to export this as
TINYINT
instead of TINYINT
UNSIGNED
. This gives you problems if you have
values larger than 127 in the column.
If you have very large (long) tables in Access, it might
take a very long time to open them. Or you might run low
on virtual memory and eventually get an ODBC
Query Failed
error and the table cannot open.
To deal with this, select the following options:
Return Matching Rows (2)
Allow BIG Results (8).
These add up to a value of 10
(OPTION=10
).
Some external articles and tips that may be useful when using Access, ODBC and Connector/ODBC:
Optimizing Access ODBC Applications
For a list of tools that can be used with Access and ODBC data sources, refer to converters section for list of available tools.
If you have problems importing data into Microsoft Excel, particularly numerical, date, and time values, this is probably because of a bug in Excel, where the column type of the source data is used to determine the data type when that data is inserted into a cell within the worksheet. The result is that Excel incorrectly identifies the content and this affects both the display format and the data when it is used within calculations.
To address this issue, use the CONCAT()
function in your queries. The use of
CONCAT()
forces Excel to treat the value
as a string, which Excel will then parse and usually
correctly identify the embedded information.
However, even with this option, some data may be incorrectly
formatted, even though the source data remains unchanged.
Use the Format Cells
option within Excel
to change the format of the displayed information.
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
do not work properly. The fix is to use
OPTION=16384
in the ODBC connect string
or to select the Change BIGINT columns to
INT
option in the Connector/ODBC connect screen.
You may also want to select the Return matching
rows
option.
If you have a BIGINT
in your result, you
may get the error [Microsoft][ODBC Driver Manager]
Driver does not support this parameter
. Try
selecting the Change BIGINT columns to
INT
option in the Connector/ODBC connect screen.
When you are coding with the ADO API and Connector/ODBC, you
need to pay attention to some default properties that aren't
supported by the MySQL server. For example, using the
CursorLocation Property
as
adUseServer
returns a result of –1
for the RecordCount Property
. To have the
right value, you need to set this property to
adUseClient
, as shown 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.
To find the number of rows affected by a specific SQL
statement in ADO, use the RecordsAffected
property in the ADO execute method. For more information on
the usage of execute method, refer to
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ado270/htm/mdmthcnnexecute.asp.
For information, see ActiveX Data Objects(ADO) Frequently Asked Questions.
You should select the Return matching
rows
option in the DSN.
For more information about how to access MySQL via ASP using Connector/ODBC, refer to the following articles:
A Frequently Asked Questions list for ASP can be found at http://support.microsoft.com/default.aspx?scid=/Support/ActiveServer/faq/data/adofaq.asp.
Some articles that may help with Visual Basic and ASP:
MySQL
BLOB columns and Visual Basic 6 by Mike Hillyer
(<mike@openwin.org>
).
How
to map Visual basic data type to MySQL types by
Mike Hillyer (<mike@openwin.org>
).
[+/-]
With all Borland applications where the Borland Database Engine (BDE) is used, follow these steps to improve compatibility:
Update to BDE 3.2 or newer.
Enable the Don't optimize column widths
option in the DSN.
Enabled the Return matching rows
option
in the DSN.
When you start a query, you can use the
Active
property or the
Open
method. Note that
Active
starts by automatically issuing a
SELECT * FROM ...
query. That may not be
a good thing if your tables are large.
Also, here is some potentially useful Delphi code that sets
up both an ODBC entry and a BDE entry for Connector/ODBC.
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);
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
Connector/ODBC for MySQL data sources. Allaire has verified
that MyODBC 2.50.26 works with MySQL 3.22.27 and ColdFusion
for Linux. (Any newer version should also work.) You can
download Connector/ODBC at
http://dev.mysql.com/downloads/connector/odbc/.
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 appears in the ODBC data sources drop-down
list, you must build and copy the Connector/ODBC driver to
/opt/coldfusion/lib/libmyodbc.so
.
The Contrib directory contains the program
mydsn-
which allows you to build and remove the DSN registry file for
the Connector/ODBC driver on ColdFusion applications.
xxx
.zip
For more information and guides on using ColdFusion and Connector/ODBC, see the following external sites:
Open Office (http://www.openoffice.org) How-to: MySQL + OpenOffice. How-to: OpenOffice + MyODBC + unixODBC.
Sambar Server (http://www.sambarserver.info) How-to: MyODBC + SambarServer + MySQL.
Ésta es una traducción del manual de referencia de MySQL, que puede encontrarse en dev.mysql.com. El manual de referencia original de MySQL está escrito en inglés, y esta traducción no necesariamente está tan actualizada como la versión original. Para cualquier sugerencia sobre la traducción y para señalar errores de cualquier tipo, no dude en dirigirse a mysql-es@vespito.com.