如何使用ROWID在Python SQLite3中编辑特定行的内容

Question

I have the following database (test.db): Test Database

As seen in the picture,I created and populated a table ("stuffToPlot").

I want to edit a specific row (the 5th row for example), and change all the values therein. I tried the following code to do this:

import sqlite3

conn = sqlite3.connect('test.db')
c = conn.cursor()

tableToEdit = 'stuffToPlot'
rowToEdit = '5'
unixVar = 5.5
dateStampVar ='feb-2018'
keywordVar = 'Hello World'
valueVar = 25

c.execute("""INSERT INTO """+tableToEdit+""" (unix, datestamp, keyword, value)
VALUES (?,?,?,?) WHERE ROWID =""" +rowToEdit),(unixVar, dateStampVar, keywordVar, valueVar) 


conn.commit()

c.close()
conn.close()

I get the following error when trying to run the code:

Traceback (most recent call last): File "C:\\Users\\Bob\\Documents\\Eclipse Workspace\\Python Test\\SQLite3\\SQLite3-3.py", line 19, in VALUES (?,?,?,?) WHERE ROWID =""" +rowToEdit),(unixVar, dateStampVar, keywordVar, valueVar) sqlite3.OperationalError: near "WHERE": syntax error

I have also tried using the UPDATE/SET method, but get a different error:

c.execute("""UPDATE """+tableToEdit+""" (unix, datestamp, keyword, value)
SET (?,?,?,?) WHERE ROWID =""" +rowToEdit),(unixVar, dateStampVar, keywordVar, valueVar)

File "C:\\Users\\Shaun\\Documents\\Eclipse Workspace\\Python Test\\SQLite3\\SQLite3-3.py", line 24, in SET (?,?,?,?) WHERE ROWID =""" +rowToEdit),(unixVar, dateStampVar, keywordVar, valueVar) sqlite3.OperationalError: near "(": syntax error

I just want to edit a specific row (using ROWID) ,any help would be greatly appreciated.

Answer 1

INSERT always adds a new row, you can't use a WHERE clause when using INSERT . So yes, you have to use UPDATE here. Your UPDATE syntax is wrong however.

UPDATE uses columname=value pairs, see the official documentation for UPDATE :

c.execute(
    """UPDATE {} SET unix=?, datestamp=?, keyword=?, value=?
       WHERE ROWID = ?""".format(tableToEdit),
    (unixVar, dateStampVar, keywordVar, valueVar, int(rowToEdit)))

I switched from using concatenation to str.format() , but only to put the table name in. The ROWID value can be passed in as a query parameter, so do so.

Demo:

>>> import sqlite3
>>> conn = sqlite3.connect(':memory:')
>>> conn.execute('''
... CREATE TABLE stuffToPlot (unix REAL, datestamp TEXT, keyword TEXT, value INTEGER)
... ''')
<sqlite3.Cursor object at 0x10f049ce0>
>>> with conn:
...     for _ in range(10):
...         c = conn.execute('''
...             INSERT INTO stuffToPlot VALUES (42.0, "mar-2010", "The quick brown fox", 81)
...         ''')
...
>>> tableToEdit = 'stuffToPlot'
>>> rowToEdit = '5'
>>> unixVar = 5.5
>>> dateStampVar ='feb-2018'
>>> keywordVar = 'Hello World'
>>> valueVar = 25
>>> with conn:
...     conn.execute(
...         """UPDATE {} SET unix=?, datestamp=?, keyword=?, value=?
...            WHERE ROWID = ?""".format(tableToEdit),
...         (unixVar, dateStampVar, keywordVar, valueVar, int(rowToEdit)))
...
<sqlite3.Cursor object at 0x10f049ce0>
>>> print(*conn.execute('SELECT * FROM stuffToPlot WHERE ROWID=5'))
(5.5, 'feb-2018', 'Hello World', 25)