I have two databases DB1 and DB2. Now there are some stored procedure and views in DB1 which are related to DB2 also like this:
SELECT ....
FROM DB1.TableA INNER JOIN DB2.TableB
.....
Now, as I have to move these two database to the other server with scripts. I have to make sure that if I am running the script of DB2 I would first run script forthat DB1 object. I am not sure if I can run the script one by one or do I need to prepare one script which will be made based on the dependency?
Any suggestion ?
If you want to generate scripts for moving data, I would suggest you use the tasks -> generate scripts option on the database you want to move. You can choose whether you to script data and schema, or just schema, whether to script indexes, foreign key relationships, and so forth. Quick guide here:
http://blog.sqlauthority.com/2011/05/07/sql-server-2008-2008-r2-create-script-to-copy-database-schema-and-all-the-objects-data-schema-stored-procedure-functions-triggers-tables-views-constraints-and-all-other-database-objects/
If I were you though, I would download the trial version of RedGate SQL Compare. It has 2 tools called Schema Compare and Data Compare, which allows you to compare 2 databases, and synchronize them schema and data wise. It is a brilliant tool, and we use it everyday to make sure our databases are in sync.
Also, if you have linked servers set up like you say above (DB1 referencing DB2), then it might be worthwhile to take both databases offline, when the traffic on the website is low.
Alternatively, you can create a replica to DB1 and DB2, using SQL Compare/Generate Scripts, and then switch your connection strings to point to the replicas, once they have been ported to the new servers. That way, the switch is instantaneous, and you do not have to take the databases offline.
Related
We are handling a data aggregation project by having several microsoft sql server databases combining to one mysql database. all mssql database have the same schema.
The requirements are :
each mssql database can be imported to mysql independently
before being able to import each record to mysql we need to validates each records with a specific createrias via php.
each imported mssql database can be rollbacked. It means even it already imported to mysql, all the mssql database can be removed from the mysql.
we would still like to know where does each record imported to the mysql come from what mssql database.
All import process will be done with PHP .
we have difficulty in many aspects. we don't know what is the best approach to solve our problem.
your help will be highly appreciated.
ps: each mssql database has around 60 tables and each table can have a few hundred thousands .
Don't use PHP as a database administration utility. Any time you build a quick PHP script to transfer records directly from one database to another, you're going to cause yourself a world of hurt when that script becomes required for production operation.
You have a number of problems that you need solved:
You have multiple MSSQL databases with similar if not identical tables.
You have a single MySQL database that you want to merge the data into.
The imported data must be altered in a specific way before being merged.
You want to prevent all duplicate records in your import.
You want to know what database each record originally came from.
The solution?
Analyze the source MSSQL databases and create a merge strategy for them.
Create a database structure on the MySQL database that fits the merge strategy in #1, including all the new key constraints (like unique and foreign keys) required for the consolidation.
At this point you have two options left:
Dump the data from each of the source databases into raw data using your RDBMS administration utility of choice. Alter that data to fit your merge strategy and constraints. Document this, and then merge all of the data into your new database structure.
Use a tool like opendbcopy to map columns from one database to another and run a mass import.
Hope this helps.
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.
I got a case where I have several databases running on the same server. There's one database for each client (company1, company2 etc). The structure of each of these databases should be identical with the same tables etc, but the data contained in each db will be different.
What I want to do is keep a master db that will contain no data, but manage the structure of all the other databases, meaning if I add, remove or alter any tables in the master db the changes will also be mirrored out to the other databases.
Example: If a table named Table1 is created in the master DB, the other databases (company1, company2 etc) will also get a table1.
Currently it is done by a script that monitors the database logs for changes made to the master database and running the same queries on each of the other databases. Looked into database replication, but from what I understand this will also bring along the data from the master database, which is not an option in this case.
Can I use some kind of logic against database schemas to do it?
So basicly what I'm asking here is:
How do I make this sync happen in the best possible way? Should I use a script monitoring the logs for changes or some other method?
How do I avoid existing data getting corrupted if a table is altered? (data getting removed if a table is dropped is okay)
Is syncing from a master database considered a good way to do what I wish (having an easy maintainable structure across several datbases)?
How will making updates like this affect the performance of the databases?
Hope my question was clear and that this is not a duplicate of some other thread. If more information and/or a better explantion of my problem is needed, let me know:)
You can get the list of tables for a given schema using:
select TABLE_NAME from information_schema.tables where TABLE_SCHEMA='<master table name>';
Use this list for a script or stored procedure ala:
create database if not exists <name>;
use <name>;
for each ( table_name in list )
create table if not exists <name>.table_name like <master_table>.table_name;
Now that Im thinking about it you might be able to put a trigger on the 'information_schema.tables' db that would call the 'create/maintain' script. Look for inserts and react accordingly.
I am very new to this and a good friend is in a bind. I am at my wits end. I have used gui's like navicat and sqlyog to do this but, only manually.
His band info data (schedules and whatnot) is in a MYSQL database on a server (admin server).
I am putting together a basic site for him written in Perl that grabs data from a database that resides on my server (public server) and displays schedule info, previous gig newsletters and some fan interaction.
He uses an administrative interface, which he likes and desires to keep, to manage the data on the admin server.
The admin server db has a bunch of tables and even table data the public db does not need.
So, I created tables on the public side that only contain relevant data.
I basically used a gui to export the data, then insert to the public side whenever he made updates to the admin db (copy and paste).
(FYI I am using DBI module to access the data in/via my public db perl script.)
I could access the admin server directly to grab only the data I need but, the whole purpose of this is to "mirror" the data not access the admin server on every query. Also, some tables are THOUSANDS of rows and parsing every row in a loop seemed too "bulky" to me. There is however a "time" column which could be utilized to compare to.
I cannot "sync" due to the fact that the structures are different, I only need the relevant table data from only three tables.
SO...... I desire to automate!
I read "copy" was a fast way but, my findings in how to implement were too advanced for my level.
I do not have the luxury of placing a script on the admin server to notify when there was an update.
1- I would like to set up a script to check a table to see if a row was updated or added on the admin servers db.
I would then desire to update or insert the new or changed data to the public servers db.
This "check" could be set up in a cron job I guess or triggered when a specific page loads on the public side. (the same sub routine called by the cron I would assume).
This data does not need to be "real time" but, if he updates something it would be nice to have it appear as quickly as possible.
I have done much reading, module research and experimenting but, here I am again at stackoverflow where I always get great advice and examples.
Much of the terminology is still quite over my head so verbose examples with explanations really help me learn quicker.
Thanks in advance.
The two terms you are looking for are either "replication" or "ETL".
First, replication approach.
Let's assume your admin server has tables T1, T2, T3 and your public server has tables TP1, TP2.
So, what you want to do (since you have different table structres as you said) is:
Take the tables from public server, and create exact copies of those tables on the admin server (TP1 and TP2).
Create a trigger on the admin server's original tables to populate the data from T1/T2/T3 into admin server's copy of TP1/TP2.
You will also need to do initial data population from T1/T2/T3 into admin server's copy of TP1/TP2. Duh.
Set up the "replication" from admin server's TP1/TP2 to public server's TP1/TP2
A different approach is to write a program (such programs are called ETL - Extract-Transform-Load) which will extract the data from T1/T2/T3 on admin server (the "E" part of "ETL"), massage the data into format suitable for loading into TP1/TP2 tables (the "T" part of "ETL"), transfer (via ftp/scp/whatnot) those files to public server, and the second half of the program (the "L") part will load the files into the tables TP1/TP2 on public server. Both halfs of the program would be launched by cron or your scheduler of choice.
There's an article with a very good example of how to start building Perl/MySQL ETL: http://oreilly.com/pub/a/databases/2007/04/12/building-a-data-warehouse-with-mysql-and-perl.html?page=2
If you prefer not to build your own, here's a list of open source ETL systems, never used any of them so no opinions on their usability/quality: http://www.manageability.org/blog/stuff/open-source-etl
I think you've misunderstood ETL as a problem domain, which is complicated, versus ETL as a one-off solution, which is often not much harder than writing a report. Unless I've totally misunderstood your problem, you don't need a general ETL solution, you need a one-off solution that works on a handful of tables and a few thousand rows. ETL and Schema mapping sound scarier than they are for a single job. (The generalization, scaling, change-management, and OLTP-to-OLAP support of ETL are where it gets especially difficult.) If you can use Perl to write a report out of a SQL database, you probably know enough to handle the ETL involved here.
1- I would like to set up a script to check a table to see if a row was updated or added on the admin servers db. I would then desire to update or insert the new or changed data to the public servers db.
If every table you need to pull from has an update timestamp column, then your cron job includes some SELECT statements with WHERE clauses based on the last time the cron job ran to get only the updates. Tables without an update timestamp will probably need a full dump.
I'd use a one-to-one table mapping unless normalization was required... just simpler to my opinion. Why complicate it with "big" schema changes if you don't have to?
some tables are THOUSANDS of rows and parsing every row in a loop seemed too "bulky" to me.
Limit your queries to only the columns you need (and if there are no BLOBs or exceptionally big columns in what you need) a few thousand rows should not be a problem via DBI with a FETCHALL method. Loop all you want locally, just make as few trips to the remote database as possible.
If a row is has a newer date, update it. I will also have to check for new rows for insertion.
Each table needs one SELECT ... WHERE updated_timestamp_columnname > last_cron_run_timestamp. That result set will contain all rows with newer timestamps, which contains newly inserted rows (if the timestamp column behaves like I'd expect). For updating your local database, check out MySQL's ON DUPLICATE KEY UPDATE syntax... this will let you do it in one step.
... how to implement were too advanced for my level ...
Yes, I have actually done this already but, I have to manually update...
Some questions to help us understand your level... Are you hitting the database from the mysql client command-line or from a GUI? Have you gotten to the point where you've wrapped your SQL queries in Perl and DBI, yet?
If the two databases have different, you'll need an ETL solution to map from one schema to another.
If the schemas are the same, all you have to do is replicate the data from one to the other.
Why not just create identical structure on the 'slave' server to the master server. Then create a small table that keeps track of the last timestamp or id for the updated tables.
Then select from the master all rows changed since the last timestamp or greater than the id. Insert them into the matching table on the slave server.
You will need to be careful of updated rows. If a row on the master is updated but the timestamp doesn't change then how will you tell which rows to fetch? If that's not an issue the process is quite simple.
If it is an issue then you need to be more sophisticated, but without knowing the data structure and update mechanism its a goose chase to give pointers on it.
The script could be called by cron every so often to update the changes.
if the database structures must be different on the two servers then a simple translation step may need to be added, but most of the time that can be done within the sql select statement and maybe a join or two.
Just some pointers here.
I am making fairly extensive modifications to a site, including the MySQL database.
My plan is to do everything on my development server, export the new MySQL structure for the db and import it onto the clients server.
Basically I need to know that performing a structure only import will not overwrite/delete existing data. I am not making changes to the data type or field length.
In my experience, when you export a database (through phpMyAdmin for instance), part of the SQL script that is created includes a "DROP TABLE IF EXISTS 'table_name';" before doing a "CREATE TABLE 'table_name'...;" to build the new table.
My guess is that this is not what you want to do! Certainly use the dev system to alter the structure in order to make everything correct, but then look around for a database synchronisation routine where you can provide the old structure, the new structure, and the software will create the appropriate "ALTER TABLE 'table_name'...;" scripts to make the required changes.
You should then really examine these change files before executing them on the live database, and of course BACKUP the live database, and ensure you are able to fully recover from the backup before starting any of the alterations!
I've had to do this a lot, and it always goes like this:
Make a backup of the live database, complete with data.
Make a backup of the live database schema only.
Calculate the differences between the old (live) schema and the new (devel) schema.
Create all of the 'ALTER TABLE ...' DDL statements necessary to upgrade from the old schema to the new one. Keep in mind that if you rename a field, you probably won't be able to just rename it -- you'll need to create the new field, copy the data from the old field, and then drop the old field.
If you changed relationships between tables, you'll probably need to drop indexes and foreign key relationships first, and then add them back afterwards.
You'll need to populate any new fields based upon their default values, if any.
Once you've got all the pieces working, you'll need to combine them into one large script, and then run it on a copy of the live database.
Dump the schema and compare it against the desired new schema -- if they don't match, go back to step 3 and repeat.
Dump the data and compare it against the expected changes -- again, if they don't match, go back to step 3 and repeat.
You're going to learn a lot more about SQL DDL/DML during this process than you ever thought you'd learn. (For one project, where we were switching from natural keys to UUID keys for 50+ tables, I ended up writing programs to generate all of the DDL/DML.)
Good luck, and make frequent backups.
I'd recommend to prepare a sql script for every change you do on development server, so you will be able to reproduce it on development. You shouldn't get to the point where you need to calculate differences between database structures
This is how I do it, all changes are reflected in sql scripts, and I can reconstruct the history of my database running all these files if needed.
Test the final release version on a "staging" mysql server. Make a copy of your production server on another machine and test your script to make sure everything's ok.
Of course, preliminary database backup is a must.