Re: [sqlalchemy] how to do housekeeping jobs before using sqlalchemy and coworking with python sqlite3 and sqlalchemy ?

[Mike Conley]

On Wed, Aug 25, 2010 at 1:30 PM, keekychen.shared <
keekychen.sha...@gmail.com> wrote:

>
> How to test if an existing "database" file is a valid sqlite3 format
> file before using sqlalchemy?
>

Here is function we use

import os, os.path as osp
try:
    from pysqlite2 import dbapi2 as sqlite
except:
    import sqlite3 as sqlite

def isSQLite(filename):
    """True if filename is a SQLite database
    File is database if: (1) file exists, (2) length is non-zero,
                        (3) can connect, (4) has sqlite_master table
    """
    # validate file exists
    if not osp.isfile(filename):
        return False
    # is not an empty file
    if not os.stat(filename).st_size:
        return False
    # can open a connection
    try:
        conn = sqlite.connect(filename)
    except:
        return False
    # has sqlite_master
    try:
        result = conn.execute('pragma table_info(sqlite_master)').fetchall()
        if len(result) == 0:
            conn.close()
            return False
    except:
        conn.close()
        return False

    # looks like a good database
    conn.close()
    return True

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