QtSql Driver Not Loaded (using OSX)

Iogogo

I am trying to use Qt to open a mysql database using Python. I am getting a

driver not loaded

error. I currently have PyQt installed on the system nad have just downloaded Qt Createor.

db = QtSql.QSqlDatabase.addDatabase("QMYSQL")
db.setHostName("localhost")
db.setDatabaseName("raw_data")
db.setUserName("root")
db.setPassword("password")
db.open()
False

I have read numerous examples here about linking issues that could potentially cause this, however I dont know how to link the files and paths together correctly to fix the issue.

Any help would be appreciated. Thank you

SGaist

Hi and welcome to devnet,

Do you have the MySQL client libraries installed ?

Iogogo

I have downloaded MySQL using homebrew and it is currently installed in

file:///usr/local/opt/mysql/

This is also the location where qt is installed as well in

file:///usr/local/opt/qt/plugins/sqldrivers/

Where currently I only see the libsqlite.dylib file and nothing else.

In the file:///usr/local/opt/mysql/ I do see a list of clinets that are installed and these are

libmysqlclient.20.dylib
libmysqlclient.a
libmysqlclient.dylib
libmysqld.a
libmysqlservices.a

However running the type -a mysql command in terminal results in

mysql is /usr/local/bin/mysql

Let me know if any more information is needed

SGaist

How did you install Qt ?

Iogogo

@SGaist I used brew install to download qt. However, I have recently downloaded Qt from the qt website and have the following link available

/users/USERNAME/Qt/5.5/clang_64/plugins/sqldrivers/

Where I have the following list of drivers

libqsqlite_debug.dylib
libqsqlite.dylib
libqsqlmysql_debug.dylib
libqsqlmysql.dylib
libqsqlodbc_debug.dylib
libqsqlodbc.dylib
libqsqlpqsql_debug.dylib
libqsqlpsql.dylib

SGaist

Using the version installed through homebrew should have the MySQL plugin working already.

As for the version you downloaded, please run tool -L on libqsqlmysql.dylib

Iogogo

After running otool -L I get the following message

libqsqlmysql.dylib:
	libqsqlmysql.dylib (compatibility version 0.0.0, current version 0.0.0)
	/opt/local/lib/mysql55/mysql/libmysqlclient.18.dylib (compatibility version 18.0.0, current version 18.0.0)
	/usr/lib/libz.1.dylib (compatibility version 1.0.0, current version 1.2.5)
	@rpath/QtSql.framework/Versions/5/QtSql (compatibility version 5.5.0, current version 5.5.1)
	@rpath/QtCore.framework/Versions/5/QtCore (compatibility version 5.5.0, current version 5.5.1)
	/System/Library/Frameworks/DiskArbitration.framework/Versions/A/DiskArbitration (compatibility version 1.0.0, current version 1.0.0)
	/System/Library/Frameworks/IOKit.framework/Versions/A/IOKit (compatibility version 1.0.0, current version 275.0.0)
	/usr/lib/libc++.1.dylib (compatibility version 1.0.0, current version 120.0.0)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1213.0.0)

SGaist

I don't know if the MySQL 20 and 18 are completely compatible but one thing you can try before rebuilding the plugin is to use install_name_tool:

install_name_tool -change /opt/local/lib/mysql55/mysql/libmysqlclient.18.dylib /usr/local/bin/mysql/libmysqlclient.20.dylib

If you are experiencing anything funky using the plugin, then rebuild it.

Iogogo

That is what I was thinking regarding the compatibility of the two versions, I will attempt the change and let you know