I need to somehow store the changes made to database structure (on CREATE, DELETE, ALTER, RENAME). The goal is to create an api that will return to a client a list of changes made to the specified database structure since some date (user_who_made_changes, changes_date, DDL_query).
Is it possible with MySQL?
Unfortunately DDL triggers are not supported in MySQL.
I also looked at logging at MySQL (general or binary logging), but it seems there's no possibility to sort logged statements by specified schema.
Any ideas? Will be thankful for any advice.
Related
I am doing research on MySQL data. I used the dbConnect function to connect to the database and used dbReadTable to read a table.
My question is: if I start cleaning data to make it tidy using tidyr and dplyr, etc, will this change the data from the database (data that is stored in mySQL and was collected by researcher)
Or does cleaning data in R only change the data called upon in R and have NO EFFECT ON THE database.
I need a definitive, well-backed, and professional answer as the data I'm dealing with is pretty important and valuable.
Given a database connection, you can definitely modify data in the database by using any of the keywords such as INSERT, UPDATE, DELETE depending on the role of the database user;
One safe way to avoid any modification of the database is ask the database administrator (I assume you are not the one) to create a user that has only read access to it, and then connect the database using this specific user. Then you would be safe to do analysis without unintentionally injecting anything into your database because the database won't allow you to do so;
But most importantly consult with the database administrator before taking next step, this answer is just for giving a clue on how to do this safely from my personal perspective. No responsibility taken for the next move you made.
I have run delete query in my table on my local system
delete from table_name
Now i want to recover it. How can i do this Please help me. I am using php mysql. Please help me
Unfortunately, no. If you were running the server in default config, go get your backups (you have backups, right?) - generally, a database doesn't keep previous versions of your data, or a revision of changes: only the current state.
(Alternately, if you have deleted the data through a custom frontend, it is quite possible that the frontend doesn't actually issue a DELETE: many tables have a is_deleted field or similar, and this is simply toggled by the frontend.
Note that this is a "soft delete" implemented in the frontend app - the data is not actually deleted in such cases; if you actually issued a DELETE, TRUNCATE or a similar SQL command, this is not applicable.
I am facing a problem for a task I have to do at work.
I have a MySQL database which holds the information of several clients of my company and I have to create a backup/restore procedure to backup and restore such information for any single client. To clarify, if my client A is losing his data, I have to be able to recover such data being sure I am not modifying the data of client B, C, ...
I am not a DB administrator, so I don't know if I can do this using standard mysql tools (such as mysqldump) or any other backup tools (such as Percona Xtrabackup).
To backup, my research (and my intuition) led my to this possibile solution:
create the restore insert statement using the insert-select syntax (http://dev.mysql.com/doc/refman/5.1/en/insert-select.html);
save this inserts into a sql file, either in proper order or allowing this script to temporarily disable the foreign key checks to meet foreign keys' constraint;
of course, I do this for all my clients on a daily base, using a file for each client (and day).
Then, in the case I have to restore the data for a specific client:
I delete all his data left;
I restore the correct data using his sql file I created during the backup.
This way I believe I may recover the right data of client A without touching the data of client B. Is my solution eventually working? Is there any better way to achieve the same result? Or do you need more information about my problem?
Please, forgive me if this question is not well-formed, but I am new here and this is my first question so I may be unprecise...thanks anyway for the help.
Note: we will also backup the entire database with mysqldump.
You can use the --where parameter, you could provide a condition like *client_id=N* . Of course I am making an assumption since you don't provide any information on your schema.
If you have a Star schema , then you could probably write a small script that backups all lookup tables (considering they are adequately small) by using this parameter --tables and use the --where condition for your client data table. For additional performance, perhaps you could partition the table by the client_id.
Recently I changed some table schema and procedures in DEV environment. Before i deploy it to production environment, I want to have a change list.
How to track or show the schema and procedures change history in MySQL? For example, show which tables have been changed after 2011-06-10, which procedures have been created or updated after 2011-06-08.
This is a longer route, but, you could you create a data dictionary. You can date them, and then represent the different schema version, or even changes to the schema. They are easily tracked with your favorite version control tool.
information_schema tables have create date fields which would get you a list of added tables and procedures etc after a particular date but modifications can't be identified by this method. However, a much simpler method would be to restore a prod backup to a different name and then use the mysqldiff utility to identify the changes.
Is there any way to automatically create a trigger on creation of new table in MySQL?
As I've pointed out in your other question, I think a process and security review is in order here. It's an audited database, so nobody (especially third-party service providers) should be creating tables in your database without your knowledge.
The issue you've got is, as well as the new table being created, you will also need to have another table created to store the audited/changed records, which will have an identical structure as the original table with possibly a time/date and user column. If a third-party provider is creating this table, they won't know to create the auditing table, therefore even if you could generate your triggers dynamically, they wouldn't work.
It's impossible to create a single table that will hold all changes record for all other tables in your database because the structure between tables inevitably differs.
Therefore: make all change requests (e.g. providers wants to create TableX, they submit a change request (including the SQL script) explaining the reason for the change) to yourself and/or your team.
You execute the SQL on a test copy of your database, and use the same structure to create another table to hold the modified records.
You then create and test the necessary triggers, generate a new SQL script to create the two tables and your triggers and execute that on your live database. You give your provider permissions to use the new table and away they go.
Everyone's happy. Yes, it may take a little while longer, and yes you'll have more work to do, but that's a hell of a lot less work than is required to try and parse query logs to re-create records that have already been changed/deleted, or parse the binary log and keep up-to-date with every change, and modify your code when the format of the log file changes etc etc.