How do you delete data from a table in MySQL?
To delete data from a table, you use the MySQL DELETE statement. The following illustrates the syntax of the DELETE statement: First, specify the table from which you delete data. Second, use a condition to specify which rows to delete in the WHERE clause.
How to see query log files in MySQL?
You have to activate the query logging in mysql. By default, all log files are created in the data directory. Check /var/lib/mysql folder. In my (I have LAMP installed) /etc/ mysql /my.cnf file I found following, commented lines in [mysqld] section:
How can I find out who dropped a table in my database?
Someone has dropped a table from your database and you want to track who did it. Or someone has deleted some data from a table, but no one will say who did. In this tip, we will look at how you can use the transaction log to track down some of this information.
Where to find deleted data in SQL Server?
All transactions which have executed a DELETE statement will display by running the above command and we can see this in the above screenshot. As we are searching for deleted data in table Location, we can see this in the last row. We can find the table name in the “AllocUnitName” column.
How to delete rows from parent table in MySQL?
For a table that has a foreign key constraint, when you delete rows from the parent table, the rows in the child table will be deleted automatically by using the ON DELETE CASCADE option. We will use the employees table in the sample database for the demonstration.
What happens when you drop a table in MySQL?
The TEMPORARY option allows you to remove temporary tables only. It ensures that you do not accidentally remove non-temporary tables. The IF EXISTS option conditionally drop a table only if it exists. If you drop a non-existing table with the IF EXISTS option, MySQL generates a NOTE, which can be retrieved using the SHOW WARNINGS statement.
When to repeat the DELETE statement in MySQL?
To ensure that a given DELETE statement does not take too much time, the MySQL-specific LIMIT row_count clause for DELETE specifies the maximum number of rows to be deleted. If the number of rows to delete is larger than the limit, repeat the DELETE statement until the number of affected rows is less than the LIMIT value.