Updates

Version 0.4.0

This version replaces the procedure (written in PL/pgSQL) assigning automatically IDs in LabxDB seq by the equivalent Python code:

The PL/pgSQL procedure is complex whereas the replacement code written in Python is simple and easy to maintain.
The Python code locks the tables to assure the generated IDs are unique. Locking happens within a Python context to make sure locks are released in case something wrong happens.

Manual update is not required but the unused procedures create_new_ids and get_next_id in seq table can be manually removed.

Version 0.3

This version introduces a new column in LabxDB order database: URL. Using a new link option for thegui_type parameter, the Table class displays URLs as buttons.

Manual update is required. Follow instructions below.

Add url in the purchase.item table.
1. Connect to PostgreSQL (your installation might be different):
```
psql -U lab postgres
```
2. Add the url column:
```
ALTER TABLE purchase.item ADD COLUMN url varchar(255);
```

Replace the following files in your installation (in this example /root/labxdb):

tar xvfz labxdb-v0.3.tar.gz
cp labxdb-v0.3/handlers/order.py /root/labxdb/handlers/
cp labxdb-v0.3/handlers/plasmid.py /root/labxdb/handlers/
cp labxdb-v0.3/static/js/table.js /root/labxdb/static/js/