smalltalk programming for the web

« Previous  |  Next »

SQLite Boolean

20 May 2018

From its documentation, SQLite does not have a separate Boolean storage class. Instead, Boolean values are stored as integers 0 (false) and 1 (true).

I've added Boolean handling to UDBC-SQLite. When writing to an SQLite database from Pharo, true is written as integer 1 and false as integer 0. SQLite uses dynamic typing, and any column in an SQLite database, except an INTEGER PRIMARY KEY column, may be used to store a value of any type, irrespective of the column's type declaration. As such, when writing Boolean values to a database, UDBC-SQLite does not check the database's type declaration.

When reading an SQLite database, UDBC-SQLite does check a column's type declaration: If a column is Boolean, UDBC-SQLite reads 1 as true, 0 as false, NULL as nil, and any other integer values raises an exception. I've encountered real world data where the string "t" means true and "f" means false for a Boolean column, so UDBC-SQLite handles these cases too.

Glorp has been similarly updated. Loading GlorpSQLite, from my development fork for now, installs both UDBC-SQLite and Glorp:

Metacello new
  repository: 'github://PierceNg/glorp-sqlite3';
  baseline: 'GlorpSQLite';

All Glorp unit tests should pass. Tested on Linux using fresh 32- and 64-bit 60540 images.

Blog comments powered by Disqus