DATA MANAGEMENT STATEMENTS
- INSERT: already seen that
- UPDATE table SET ... WHERE ...
- DELETE FROM table WHERE ...
- caution: these operate on whole tables if unqualified
- strategies to avoid catastrophes
-- just subconsciouly be careful, like holding a kitchen knife
-- put comment in front: -- DELETE FROM ..., then remove comment
-- do SELECT first, then replace SELECT with DELETE <- allows inspection
   of what's about to be deleted
-- tweak table name, put x in front, then remove

I/O
- all RDBMSs have scriptable I/O tools
- generally, INSERT one at a time is slow
- output to CSV
-- COPY Species TO 'species_fixed.csv' (HEADER, DELIMITER ',');
- loading CSVs: see build script
-- 1. CREATE a new empty table in the database:
CREATE TABLE Snow_cover (
    Site VARCHAR NOT NULL,
    Year INTEGER NOT NULL CHECK (Year BETWEEN 1950 AND 2015),
    Date DATE NOT NULL,
    Plot VARCHAR, -- some Null in the data :/
    Location VARCHAR NOT NULL,
    Snow_cover INTEGER CHECK (Snow_cover > -1 AND Snow_cover < 101),
    Observer VARCHAR
);
-- 2. Copy the data from a csv
COPY Snow_cover FROM 'snow_cover_fixedman_JB.csv' (header TRUE); 
NOTE: If you run this last lines several times you will keep adding the data to the table!!!

TRIGGERS
- on some event, take some action(s)
- event: insert, update, delete on some table
- action: insert or update in same table or any other table
- example: SQLite imports empty columns as empty strings, not NULLs,
  which is lame
- database.db build script (look at it) does post-import updates
- trigger approach!
- can't play with real Species table due to foreign keys
-- .import --csv species.csv new_species
- .nullvalue --NULL--
- notice no NULLs!
- CREATE TRIGGER fix_species
      AFTER INSERT ON new_species
      FOR EACH ROW
      BEGIN
          UPDATE new_species
          SET Scientific_name = NULL
          WHERE Code = new.Code AND Scientific_name = '';
      END;