Mercurial > sqlpython
changeset 282:4eef08cfaf25
copied documentation from blog
author | catherine@dellzilla |
---|---|
date | Thu, 19 Mar 2009 16:56:36 -0400 |
parents | 701f0aae837a |
children | 80484bc60bdd |
files | docs/source/capabilities.rst |
diffstat | 1 files changed, 116 insertions(+), 6 deletions(-) [+] |
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--- a/docs/source/capabilities.rst Thu Mar 19 16:45:45 2009 -0400 +++ b/docs/source/capabilities.rst Thu Mar 19 16:56:36 2009 -0400 @@ -243,16 +243,126 @@ ======== Wild SQL is a nonstandard SQL feature that must be enabled with `set wildsql on`. When it is -enabled, column names in a SELECT statement do not need to be explicitly typed. +enabled, column names in a SELECT statement do not need to be explicitly typed; they can be +specified with special Wild SQL symbols: wildcards (`*`, `%`, `_`); column numbers (`#{N}`); +and NOT-style exclusion (`!`). The symbols can even be combined. -* % or \* as wildcards:: +:: - SELECT d* FROM v$database; + jrrt@orcl> cat party + + NAME STR INT WIS DEX CON CHA + ------- --- --- --- --- --- --- + Frodo 8 14 16 15 14 16 + Gimli 17 12 10 11 17 11 + Legolas 13 15 14 18 15 17 + Sam 11 9 14 11 16 13 + + 4 rows selected. + + jrrt@orcl> set wild on + wildsql - was: False + now: True + jrrt@orcl> select *i* from party; + + INT WIS + --- --- + 14 16 + 12 10 + 15 14 + 9 14 + + 4 rows selected. + + jrrt@orcl> select #1, #5 from party; + + NAME DEX + ------- --- + Frodo 15 + Gimli 11 + Legolas 18 + Sam 11 + + 4 rows selected. + + jrrt@orcl> select !str from party; + + NAME INT WIS DEX CON CHA + ------- --- --- --- --- --- + Frodo 14 16 15 14 16 + Gimli 12 10 11 17 11 + Legolas 15 14 18 15 17 + Sam 9 14 11 16 13 + + 4 rows selected. + + jrrt@orcl> select n*, !#3, !c* from party; + + NAME STR WIS DEX + ------- --- --- --- + Frodo 8 16 15 + Gimli 17 10 11 + Legolas 13 14 18 + Sam 11 14 11 + + 4 rows selected. - SELECT +Wild SQL symbols only work in the first SELECT statement in a query; they do not work in +subqueries, subsequent UNIONed queries, etc. + +Python +====== + +The `py` command allows the user to execute Python commands, either one-at-a-time (with +`py {command}`) or in an interactive environment (beginning with a bare `py` statement, +and continuing until `end py` is entered). + +A history of result sets from each query is exposed to the python session as the list `r`; +the most recent result set is `r[-1]`. Bind variables are exposed as the dictionary `binds`. +All variables are retained each time the python environment is entered (whether interactively, +or with one-line `py` statements). + +Resultsets in `r` are read-only, but `binds` can be written as well as read, and will +be working bind variables in the SQL environment. + +:: -Wild SQL can only be used in the primary column list of straightforward SELECT statements, -not in subqueries, `UNION`ed queries, etc. + 0:testschema@eqtest> select title, author from play; + + TITLE AUTHOR + --------------- ----------- + Timon of Athens Shakespeare + Twelfth Night Shakespeare + The Tempest Shakespeare + Agamemnon Aeschylus + + 4 rows selected. + + 0:testschema@eqtest> py import urllib + 0:testschema@eqtest> py current_season = urllib.urlopen('http://cincyshakes.com/').read() + 0:testschema@eqtest> py + Now accepting python commands; end with `end py` + >>> r[-1] + [('Timon of Athens', 'Shakespeare'), ('Twelfth Night', 'Shakespeare'), ('The Tempest', 'Shakespeare'), ('Agamemnon', 'Aeschylus')] + >>> for row in r[-1]: + ... print '%s by %s' % (row.title, row.author) + Timon of Athens by Shakespeare + Twelfth Night by Shakespeare + The Tempest by Shakespeare + Agamemnon by Aeschylus + >>> [row.title for row in r[-1] if row.title in current_season] + ['Timon of Athens', 'Twelfth Night'] + >>> binds['nowplaying'] = [row.title for row in r[-1] if row.title in current_season][0] + >>> end py + 0:testschema@eqtest> print + :nowplaying = Timon of Athens + 0:testschema@eqtest> select title, author from play where title = :nowplaying; + + TITLE AUTHOR + --------------- ----------- + Timon of Athens Shakespeare + + 1 row selected. Parameters ==========