A Cursor instance has the following attributes and methods:
sql, [parameters]) |
Executes a SQL statement. The SQL statement may be parametrized (i. e. placeholders instead of SQL literals). The sqlite3 module supports two kinds of placeholders: question marks (qmark style) and named placeholders (named style).
This example shows how to use parameters with qmark style:
import sqlite3 con = sqlite3.connect("mydb") cur = con.cursor() who = "Yeltsin" age = 72 cur.execute("select name_last, age from people where name_last=? and age=?", (who, age)) print cur.fetchone()
This example shows how to use the named style:
import sqlite3 con = sqlite3.connect("mydb") cur = con.cursor() who = "Yeltsin" age = 72 cur.execute("select name_last, age from people where name_last=:who and age=:age", {"who": who, "age": age}) print cur.fetchone()
execute() will only execute a single SQL statement. If you try to execute more than one statement with it, it will raise a Warning. Use executescript() if you want to execute multiple SQL statements with one call.
sql, seq_of_parameters) |
import sqlite3 class IterChars: def __init__(self): self.count = ord('a') def __iter__(self): return self def next(self): if self.count > ord('z'): raise StopIteration self.count += 1 return (chr(self.count - 1),) # this is a 1-tuple con = sqlite3.connect(":memory:") cur = con.cursor() cur.execute("create table characters(c)") theIter = IterChars() cur.executemany("insert into characters(c) values (?)", theIter) cur.execute("select c from characters") print cur.fetchall()
Here's a shorter example using a generator:
import sqlite3 def char_generator(): import string for c in string.letters[:26]: yield (c,) con = sqlite3.connect(":memory:") cur = con.cursor() cur.execute("create table characters(c)") cur.executemany("insert into characters(c) values (?)", char_generator()) cur.execute("select c from characters") print cur.fetchall()
sql_script) |
This is a nonstandard convenience method for executing multiple SQL statements at once. It issues a COMMIT statement first, then executes the SQL script it gets as a parameter.
sql_script can be a bytestring or a Unicode string.
Example:
import sqlite3 con = sqlite3.connect(":memory:") cur = con.cursor() cur.executescript(""" create table person( firstname, lastname, age ); create table book( title, author, published ); insert into book(title, author, published) values ( 'Dirk Gently''s Holistic Detective Agency', 'Douglas Adams', 1987 ); """)
For SELECT
statements, rowcount is always None because we cannot
determine the number of rows a query produced until all rows were fetched.
For DELETE
statements, SQLite reports rowcount as 0 if you make a
DELETE FROM table
without any condition.
For executemany statements, the number of modifications are summed up into rowcount.
As required by the Python DB API Spec, the rowcount attribute "is -1 in case no executeXX() has been performed on the cursor or the rowcount of the last operation is not determinable by the interface".
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