About

The eLog library was initially developed as a research prototype and later published for lifelogging researchers in 2010 to help them easily analyze heterogenous data and complex visualization. It has been kept growing with the progress of mobile computing environments and recently its UI part is released with GPL v3 license for wider usage. The eLog UI library is optimized for mobile environment and can get easily integrated with existing Web services.

Who We Are

The original work was proposed by Pil Ho and later extended the work with collaboration with 28 researchers around the world who contributed their lifelogs, collaborated for lifelog analysis and share research results to build up an open lifelogging platform for the public. Pil Ho has been keeping the development updating the library following up the progress in mobile computing.

Updates

  • Nov. 2014: Change the web page skin using bootstrap.
  • Nov. 2014: Published elog UI library as GPL v3.
  • Oct. 2014: Version up eLog library and documentation.

 

Practice in importing and exporting database tables that include "TIMESTAMP" field

To keep a long story short, I made this mistake a number of times even when handling billions of records. So here is a record for prevention :)

When exporting or importing table data that include TIMESTAMP field in there, MySQL by defaults exports the data based on UTC. It internally executes "SET time_zone='UTC'" command before exporting any data. This is a default behavior (See https://dev.mysql.com/doc/refman/5.6/en/mysqldump.html#option_mysqldump_tz-utc) and so after using mysqldump to export data, you MUST set "SET time_zone='UTC'" before importing (using LOAD DATA) the data to any database.

ex) exporting data:
mysqldump --opt -Q -h 127.0.0.1 --user=youruseid --password=yourpassword --no-create-info --where="unixtimestamp < 1373925599" --tab="/wheretosave/tmp" --fields-terminated-by="\t" --fields-optionally-enclosed-by="\"" --lines-terminated-by="\n" yourdb yourtable

Then when importing data within MySQL console:

mysql> SET time_zone="UTC";
mysql> USE yourdb;
mysql> LOAD DATA LOCAL INFILE '/wheretosave/tmp/yourtable.txt' INTO TABLE yourtable FIELDS TERMINATED BY '\t' OPTIONALLY ENCLOSED BY '\"' LINES TERMINATED BY '\n';