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Archived:How to make an interactive SQL shell using PySymbian

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Archived.pngAquivado: Este artigo foi arquivado, pois o conteúdo não é mais considerado relevante para se criar soluções comerciais atuais. Se você achar que este artigo ainda é importante, inclua o template {{ForArchiveReview|escreva a sua justificativa}}.

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Created: cyke64 (31 Mar 2007)
Last edited: hamishwillee (31 May 2013)

To learn more easily the default SQL database you can make a small script to act as an interactive SQL shell in the command line interpreter !

First create the test db file with db.create(...). Then type in these lines below in the command line interpreter.

>>> import e32db
>>> db = e32db.Dbms()
>>> dbv = e32db.Db_view()
>>> db.open(u'C:\\test.db')

Here's the query simplification code.

def Q(sql):
if sql.upper().startswith('SELECT'):
dbv.prepare(db, unicode(sql))
dbv.first_line()
rows = []
maxlen = [0] * dbv.col_count()
for i in range(dbv.count_line()):
dbv.get_line()
result = []
for i in range(dbv.col_count()):
try:
val = dbv.col(i+1)
except: # in case coltype 16
val = None
result.append(val)
maxlen[i] = max(maxlen[i], len(str(val)))
rows.append(result)
dbv.next_line()
fmt = '|'+ '|'.join(['%%%ds' % n for n in maxlen]) + '|'
for row in rows:
print fmt % tuple(row)
else:
n = db.execute(unicode(sql))
print '%d rows affected' % n

After that, playing with SQL is quite simple.

>>> Q("CREATE TABLE phone (id COUNTER, name VARCHAR, edition VARCHAR )")
0 rows affected
>>> Q("INSERT INTO phone (name,edition) VALUES ('N6600','2nd')")
1 rows affected
>>> Q("INSERT INTO phone (name,edition) VALUES ('N93','3rd')")
1 rows affected
>>> Q("SELECT * from phone")
|0| 6600| 2nd|
|1| N93| 3rd|
This page was last modified on 31 May 2013, at 04:09.
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