python将数据插入sqlite3表

Question

I am using python 3.7 and sqlite3 to write data to my database. I have this function

def add_item(self, item):
    stmt = "INSERT INTO users (id) VALUES (?)"
    args = (item,)
    self.conn.execute(stmt, args)
    self.conn.commit()

It works fine but it only allows me to write data to id column. How can I make this function dynamic so that I can add any data to any column?

# new variable to specify column to write to

def add_item(self, item, column):
    stmt = "INSERT INTO users (column) VALUES (?)"
    args = (item,)
    self.conn.execute(stmt, args)
    self.conn.commit()

Answer 1

You need to build the list of column names and value placeholders dynamically, based on the lengths of the lists of columns and values provided.

This is can be done using str.join , however you may need to handle the case where a caller passes a single string as a column name, and a single value.

def add_item(self, values, columns):
    # Check for single column insert
    if isinstance(columns, str):
        values, columns = (values,), (columns,)
    assert len(values) == len(columns), 'Mismatch between values and columns'

    template = """INSERT INTO users ({}) VALUES ({})"""

    cols = ','.join([f'"{col}"' for col in columns])
    placeholders = ','.join(['?'] * len(values))
    stmt = template.format(cols, placeholders)

    self.conn.execute(stmt, values)
    self.conn.commit()
    return