I just updated the JDBC driver for my application from
mysql-connector-java-3.1.12-bin.jar
to
mysql-connector-java-5.1.34-bin.jar.
With the v3.x driver, this kind of a query works:
select concat("<a href>", count(sakila.payment.payment_id), "</a>")
from sakila.payment;
But now with the new v5.x driver, the query only works with a cast().
select cast(concat("<a href>", count(sakila.payment.payment_id), "</a>")
as char(30)) from sakila.payment;
Is there any property in the MySQL database I can change?
I don't want to change hundreds of queries like that.
I suspect that you will have to bite the bullet and update your code. There is a bug report here that seems to match your circumstances and the status of that bug report is "Won't fix". The response from the developers ([4 Apr 2007 17:43] Reggie Burnett) was:
This is something that we can't really fix. Let me explain.
MySQL has several issues when it comes to reporting whether a result if binary or not. This was very bad on MySQL versions prior to 5.0 but it's still a problem even today. The SQL you reported is returned by MySQL as binary when it obviously is not. The connector can't know for sure. With 5.0.5 and 5.0.6, we tried to make a "best guess" but that code caused more problems than it solved, so with 5.0.7 we have rolled it out. Your SQL will return string properly with 5.0.7, but that doesn't mean it's fixed. In fact, it returns string because we are ignoring the binary flag so that means you could generate valid SQL that should return binary and 5.0.7 will return string.
Until the server is fixed, the connector just can't always do the right thing. I hope this has cleared it up somewhat.
Related
I have two PC's both of them with Win2008 R2 set it up exactly the same.
On one PC the sum(FIELD_NAME) returns a decimal number (CORRECTY) on the other
the same sum(FIELD_NAME) returns the same number as STRING !!!
I have set the System_Time_Zone to be the same on both PC (GTB Standard Time) but the problem still exist. I had uninstall and install back again MySQL on the second PC but still no luck.
I had try tzutil (O/S command) and set the time zone to the above desired but still have the same problem.
With show variables like "%time_zone%" the correct pc shows
system_time_zone : GTB Standard Time
time_zone : System
the "wrong" pc shows
system_time_zone : AN EMPTY SPACE
time_zone : System
my final solution is to reinstal Windows again but.... :o((((
any suggestions ?????
I suggest you confirm the version of the MySQL Connector you are using (not clear whether you are using the Connector/ODBC, Connector/Net or Connector/J.
What MySQL returns is interpreted/translated by the Connector. I think the issue is likely a differnce in the connector being used, or the verison of the connector, or possibly just a difference in the configuration of the Connector (for example, the DFLT_BIGINT_BIND_STR parameter in Connector/ODBC.)
(Less likely, the behavior you observe could be due to a difference in the characterset encodings.)
The details for configuration, debugging and tracing are different for each Connector.
http://dev.mysql.com/doc/index-connectors.html
I'm using Entity Framework with MySQL, and my Linq Query:
db.Persons.Where(x => x.Surname.StartsWith("Zyw")).ToList();
..is producing the SQL:
SELECT PersonId, Forename, Surname
FROM Person
WHERE (LOCATE('Zyw', Surname)) = 1
...and it would seem that this doesn't make use of the index on Surname.
If LOCATE is replaced with the equivalent LIKE, the query speedily returns the required results. As it is it takes all afternoon.
Why is Entity Framework and its connecting drivers opting for this wierd LOCATE function / how can I make it use LIKE instead / why is MySQL making a poor index decision for the LOCATE function / how can I make it better?
Update:
I'm afraid I was guilty of over simplifying my code for this post, the Linq producing the error is in fact:
var target = "Zyw";
db.Persons.Where(x => x.Surname.StartsWith(target)).ToList();
If target term is hard coded, the SQL generated does indeed use LIKE, but with a variable term the SQL changes to use LOCATE.
This is all using the latest generally available MySQL for Windows as delivered by MySQL Installer 5.6.15.
Update:
A couple more notes to go with the bounty; am using:
Visual Studio 2010
EntityFramework 6.0.2
MySQL Installer 5.6.15,
which in turn gives:
MySql.Data 6.7.4
MySql.Data.Entities 6.7.4
The Entity Framework code is generated database first style.
I've also tried it with the latest connector from Nuget (MySql.Data 6.8.3) and the problem is still there.
It's likely your problem is caused by:
You are using an older connector with the bug.
You have a special case (using a variable to hold the .Contains search) described as a bug here
Does your case fall into any of those?
This looks like a regression of MySQL bug #64935 to me.
I can confirm that, using the same builds of EF6 and MySQL Connector, I'm getting the same SQL generated too:
context.stoppoints.Where(sp => sp.derivedName.StartsWith(stopName));
...logs as:
SELECT
`Extent1`.`primaryCode`,
...
`Extent1`.`stop_timezone`
FROM `stoppoints` AS `Extent1`
WHERE (LOCATE(#p__linq__0, `Extent1`.`derivedName`)) = 1
Entity Framework: 6.0.2
MySQL Connector.Net: 6.8.3
I have reported this as a MySQL bug regression.
I have completed migrating database from sqlserver to mysql but it seems to have problems in rails. When i fetch record in rails console for eg:
<AuthAdmin:0xb6e506f8 #attributes={"Status"=>"1", "LastUpdateSeqNo"=>nil, "CreationDate"=>"2005-08-03 22:53:57", "AuthAdminID"=>"8987", "PropertyID"=>nil, "Password"=>"trustbss", "LastUpdate"=>"2012-07-12 05:15:02", "UserType"=>"0", "LoginName"=>"dev"}
Now attributes such as CreationDate and AuthAdminID suppose to be date and integer are displaying as string.But when I do
AuthAdmin.find(:first).AuthAdminID.class output is Fixnum
You can check record given above,it shows string. Now when i do arithmatic operation in my views caught issue string can't be coerced into Fixnum.Explicitly changing everything to their own TYPE is a very bad idea.
Hope that explain my problem.
Look like no one come across this problem.
We've just upgraded from Access 2003 to Access 2010 and string comparisons are failing with an invalid procedure call error when default conditions are used. I’ve recreated two presumably related problems in a new Access 2007 format database containing only the default table, a query with the SQL below and a module containing only the code below, so I seriously doubt that this is a corruption issue.
First the following sub fails on the If Then line with Run-time error 5: Invalid procedure call or argument
Option Compare Database
Option Explicit
Sub checkStrCmp()
Dim str As String
str = "s"
If str = "s" Then
MsgBox "works"
End If
End Sub
If I change Option Compare Database to Option Compare Text the sub works as expected, but this seems like a bad idea as I may want to preform text as well as numeric comparisons inside a single sub.
I’m also getting “Invalid procedure call” errors in string comparison functions inside of SQL. The Replace function is requiring the supposedly optional compare parameter.
Select replace("foo-bar-baz", "-", "|", 1,-1);
Generates the “Invalid procedure call” error
Setting the compare parameter to any of the available values (0 -3) works as expected:
SELECT replace("foo-bar-baz", "-", "|", 1,-1, 0);
produces “foo|bar|baz”
Has anyone else seen this? Is there a setting that needs to be tweaked? Any other ideas outside of “Database corruption” which is all I’ve been able to find via Google.
TIA
apoligies for the sloppy code blocks I can't for the life of me get them to work right.
UPDATE: I should have mentioned that I'm running XP Pro sp3.
The problem seems limited to databases I create on my box. When I opened the test database I created on my box from other workstations on our network I saw the issue, but was then unable to recreate it when creating a new database as described above on those workstations. The databases I created on the two other workstations (same OS and MS Office versions installed) also worked correctly when opened on my machine. I was also unable to recreate the issue when I inserted new modules in those DBs from my machine.
In short the problem seems to only exist on databases created on my machine (and in old 2003 format databases I've converted to 2007 format on my machine). My best guess is that my install is hosed but I’d like to have some idea of how and why before I approach IT with a request to reinstall Office. I’d also like to rule out a conflict with other software on my box.
Your code modules do not all need to share the same Option Compare setting. So you could place those procedures which should use text comparisons in a module which has Option Compare Text in its Declarations section.
However, I don't understand your statement, "I may want to preform text as well as numeric comparisons inside a single sub." According to Access' help topic, the Option Compare Statement is "Used at module level to declare the default comparison method to use when string data is compared". In other words, Option Compare has no effect on the comparisons of numeric values.
Edit: Since the problem is limited to Option Compare Database for database files created on only one machine, I'll suggest you check Access' "New database sort order" setting on that machine. Change it to a choice which starts with "General" if it is set to anything else. Then create a new database and see whether you still have the problem.
The reason for this suggestion is that Option Compare Database tells Access to use the database's codepage setting for sorting. And "New database sort order" can set the codepage to the one which never gives me such troubles. However, my understanding of codepage details is pretty shallow; I never change it and don't know what the consequences of other settings would be.
I am using the RJDBC package to connect to a MySQL (Maria DB) database in R on a Windows 7 machine and I am trying a statement like
select a as b
from table
but the column will always continue to be named "a" in the data frame.
This works normally with RODBC and RMySQL but doesn't work with RJDBC. Unfortunately, I have to use RJDBC as this is the only package that has no problem with the encoding of chinese, hebrew and so on letters (set names and so on don't seem to work with RODBC and RMySQL).
Has anybody experienced this problem?
I have run into the same frustrating issue. Sometimes the AS keyword would have its intended effect, but other times it wouldn't. I was unable to identify the conditions to make it work correctly.
Short Answer: (Thanks to Simon Urbanek (package maintainer for RJDBC), Yev, and Sebastien! See the Long Answer.) One thing that you may try is to open your JDBC connection using ?useOldAliasMetadataBehavior=true in your connection string. Example:
drv <- JDBC("com.mysql.jdbc.Driver", "C:/JDBC/mysql-connector-java-5.1.18-bin.jar", identifier.quote="`")
conn <- dbConnect(drv, "jdbc:mysql://server/schema?useOldAliasMetadataBehavior=true", "username", "password")
query <- "SELECT `a` AS `b` FROM table"
result <- dbGetQuery(conn, query)
dbDisconnect(conn)
This ended up working for me! See more details, including caveats, in the Long Answer.
Long Answer: I tried all sorts of stuff, including making views, changing queries, using JOIN statements, NOT using JOIN statements, using ORDER BY and GROUP BY statements, etc. I was never able to figure out why some of my queries were able to rename columns and others weren't.
I contacted the package maintainer (Simon Urbanek.) Here is what he said:
In the vast majority of cases this is an issue in the JBDC driver, because there is really not much RJDBC can do other than to call the driver.
He then recommended that I make sure I had the most recent JDBC driver for MySQL. I did have the most recent version. However, it got me thinking "maybe it IS a bug with the JDBC driver." So, I searched Google for: mysql jdbc driver bug alias.
The top result for this query was an entry at bugs.mysql.com. Yev, using MySQL 5.1.22, says that when he upgraded from driver version 5.0.4 to 5.1.5, his column aliases stopped working. Asked if it was a bug.
Sebastien replied, "No, it's not a bug! It's a documented change of behavior in all subsequent versions of the driver." and suggested using ?useOldAliasMetadataBehavior=true, citing documentation for the JDBC driver.
Caveat Lector: The documentation for the JDBC driver states that
useColumnNamesInFindColumn is preferred over useOldAliasMetadataBehavior unless you need the specific behavior that it provides with respect to ResultSetMetadata.
I haven't had the time to fully research what this means. In other words, I don't know what all of the ramifications are of using useOldAliasMetadataBehavior=true are. Use at your own risk. Does someone else have more information?
I don't know RJDBC, but in some cases when it is necessary to give permanent aliases to columns without renaming them, you can use VIEWs
CREATE OR REPLACE VIEW v_table AS
SELECT a AS b
FROM table
... and then ...
SELECT b FROM v_table
There is a separate function in the ResultSetMetaData interface for retrieving the column label vs the column name:
String getColumnLabel(int column) throws SQLException;
Gets the designated column's suggested title for use in printouts and
displays. The suggested title is usually specified by the SQL AS
clause. If a SQL AS is not specified, the value returned
fromgetColumnLabel will be the same as the value returned by the
getColumnName method.
Using getColumnLabel should resolve this issue (if not, check that your JDBC driver is following this spec).
e.g.
ResultSetMetaData rsmd = rs.getMetaData();
int columnCount = rsmd.getColumnCount();
while(rs.next()) {
for (int i = 1; i < columnCount + 1; i++) {
String label = rsmd.getColumnLabel(i);
System.out.println(rs.getString(label));
}
}
This is the work around we use for R and SAP HANA via RJDBC:
names(result)[1]<-"b"
It's not the nicest work around, but since Aaron's solution does work for us, we went with this "solution".