从所有表中删除条目

Question

I'm writing a python script that would reset the database to an initial state (some hardcoded entries in every table). The db consists of multiple tables with primary and foreign keys.

Every time I would run the script, it should remove all the old entries in all of the tables, reset the primary key counter and insert the sample entries.

Currently I am trying to achieve this like this:

# Delete all the entries from the tables 
cursor.execute("DELETE FROM table1")  
cursor.execute("DELETE FROM table2")  
cursor.execute("DELETE FROM table3")

# Reset the primary key counter and insert sample entries
cursor.execute("ALTER TABLE table1 AUTO_INCREMENT = 1") 
cursor.execute("INSERT INTO table1(username, password) VALUES('user01', '123')")

cursor.execute("ALTER TABLE table2 AUTO_INCREMENT = 1") 
cursor.execute("INSERT INTO table2(column1, column2) VALUES('column1_data', 'column2_data')")

This isn't working due to the presence of foreign keys in some tables (it won't let me delete them).

I generate the tables using a models.py script (I also use Django), so I thought I could solve this the following way:

1. remove the database programatically and create a new one with the same name
2. call the models.py script to generate empty tables in the db
3. insert sample data using the script I wrote

Is this a good solution or am I overlooking something?

Answer 1

I use scripts monthly to purge a transaction table, after archiving the contents.

Try using the 'truncate' command, ie.

truncate table [tablename];

It resets the counter (auto-increment) for primary key, automatically. Then use your insert statements to populate base info.

Also, this preserves all of the table base settings (keys,indexes,.).