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mysqlweka

Cannot connect to MySQL with Weka

I am trying to connect a database to Weka 3.6.13 in Linux Elementary OS.

First, I had a problem with JDBC connection, solved by this answer changing the /usr/bin/weka file.

Now, when I load the database, this error comes:

Unknown data type: INT. Add entry in weka/experiment/DatabaseUtils.props.

However, I am trying to use explorer only, this file doesn't even exists in my installation.

I installed via sudo apt install weka.

What should I do?

enter image description here

Solution

  • Look inside the directory where your weka.jar file resides, and check if there exists a file called DatabaseUtils.props.

    The Weka wiki says:

    Weka only looks for the DatabaseUtils.props file. If you take one of the example files listed above, you need to rename it first.

    My file is different I think the actual name does not really matter, it's the filename extension that matters.

    In my version of this file there is a section that looks like this:

    ... (snip...
# mysql-conversion / type-mappings
CHAR=0
TEXT=0
VARCHAR=0
STRING=0
LONGVARCHAR=9
BINARY=0
VARBINARY=0
LONGVARBINARY=9
BIT=1
BOOL=1
NUMERIC=2
DECIMAL=2
FLOAT=2
DOUBLE=2
TINYINT=3
SMALLINT=4
#SHORT=4
SHORT=5
INTEGER=5
INT=5
BIGINT=6
LONG=6
REAL=7
DATE=8
TIME=10
TIMESTAMP=11

#mappings for table creation
CREATE_STRING=TEXT
CREATE_INT=INT
CREATE_DOUBLE=DOUBLE
CREATE_DATE=DATETIME
DateFormat=yyyy-MM-dd HH:mm:ss

#database flags
checkUpperCaseNames=false
checkLowerCaseNames=false
checkForTable=true
setAutoCommit=true
createIndex=false

# All the reserved keywords for this database
Keywords=\
  AND,\
  ASC,\
  BY,\
  DESC,\
  FROM,\
  GROUP,\
  INSERT,\
  ORDER,\
  SELECT,\
  UPDATE,\
  WHERE

# The character to append to attribute names to avoid exceptions due to
# clashes between keywords and attribute names
KeywordsMaskChar=_

#flags for loading and saving instances using DatabaseLoader/Saver
nominalToStringLimit=50
idColumn=auto_generated_id

    If you do a google search for this file, another guy has posted his on github. The weka Wiki or SVN/Git-Repo might also list an offfical version somewhere (cannot find it right now), or you can open your weka.jar file as a zip file and extract the .props file (/src/main/java/weka/experiment/DatabaseUtils.props.mysql).

    In any case, Mysql exists in many different versions, and I think you can even switch the query engine inside mysql. So I cannot express any guarantees that any of these 2 .props files shown here really work for you. You should experiment a bit.