Python EXECUTEMANY doesn't work

[Kyle Felipe Vieira Roberto]

Hi guys!
I was helping @Yjmenezes with a python code and i had a problem with the folow code:

distancia = [] 
for i in range(145, 13000, 145): 
     distancia.append((float(i)/100))
sql = """INSERT INTO linhas_paralelas(geom) 
         SELECT ST_OffsetCurve(geometry,?) from paracatu;""" 
con.executesmany(sql, distancia) 
con.commit() 
con.close()


So, when use the executemany, the lines are not created, but, if use the follow code, works well.

distancia = []
for i in range(145, 13000, 145):
     distancia.append((float(i) / 100))
sql2 = ""
for i in distancia:
 sql2 += """INSERT INTO linhas_paralelas(geom)
SELECT ST_OffsetCurve(geometry,{dist}) from paracatu;\n""".format(dist=i)
con.executescript(sql2)
con.commit()
con.close()

There is a way to use the executemany??
Im using:
Python 2.7

package: sqlite3
SQLITE VERSION: 3.16.2

SPATIALITE VERSION: 4.3.0a 

Here is a link to github - https://github.com/kylefelipe/qgis-tips-tricks/tree/master/python/paralelas

[a.fu...@lqt.it]

On Tue, 20 Feb 2018 05:55:47 -0800 (PST), Kyle Felipe Vieira Roberto
wrote:

> Hi guys!
> I was helping @Yjmenezes with a python code and i had a problem with
> the folow code:
>
> distancia = []
> for i in range(145, 13000, 145):
>      distancia.append((float(i)/100))
> sql = """INSERT INTO linhas_paralelas(geom)
>          SELECT ST_OffsetCurve(geometry,?) from paracatu;"""
> con.executesmany(sql, distancia)
> con.commit()
> con.close()
>

Hi Kyle,

I'm not a Python programmer, so I've just tested a very
simple script.
it seems that "executemany" always expects that at least
_TWO_ bindings must be specified for each row.

test #1
=========
distancia = [1.1, 2.2, 3.3)

sql = """INSERT INTO linhas_paralelas(geom)
SELECT ST_OffsetCurve(geometry,?) from paracatu;"""
con.executesmany(sql, distancia)

this fails, returning this error message:
"Incorrect number of bindigs supplied. The current statement
uses 1, and there are 3 supplied."


test #2
=========
distancia = [(1.1), (2.2), (3.3))

sql = """INSERT INTO linhas_paralelas(geom)
SELECT ST_OffsetCurve(geometry,?) from paracatu;"""
con.executesmany(sql, distancia)

same errore as above.


test #3
=========
distancia = [(None, 1.1), (None, 2.2), (None, 3.3))
sql = """INSERT INTO linhas_paralelas(id, geom)
SELECT ?, ST_OffsetCurve(geometry,?) from paracatu;"""
con.executesmany(sql, distancia)

and finally this last test nicely works; but as you
can easily notice wa are now using 2 bindings for
each row.
I strongly suspect that this odd behavior is someway
related to Python arrays, but my personal skills about
this language are too limited to say any more.

bye Sandro

[Kyle Felipe Vieira Roberto]

@Sandro.
I did not pay atention  to python docs, there thy show the right way usage..
so your last code example is correct.

[Kyle Felipe Vieira Roberto]

@All..

Here is the full code..

https://github.com/kylefelipe/qgis-tips-tricks/blob/master/python/paralelas/linhas_paralelas.py