I have a database diagram in Workbench and this diagram is synchronized with my database. This database has more than 500 tables, and I need to add a new column to most tables, it is not a viable option to add it one by one and then synchronize the changes with the database. Is there any workbench option that allows me to add the field in bulk to many tables ?.
The only way I can think of is to make a script that automatically adds that attribute to the tables and then perform the inverse synchronization, that is, update the diagram from the database.
What do you think? Any better solution?
Related
I have three identical tables, one on MySQL, one linked to this one on Access by ODBC, and a native in the same Access database.
When I update the table on MySQL, the linked table on Access updates, and vice versa. But I would like to know if it is possible that the linked table updates the native table (and vice versa)?
Access table
MySQL table
It really depends on how the local Access table is being updated. If it is ALWAYS updated say by a few forms, then you could add a after update even to those few forms, and put in code to update the MySQL table.
Another approch (again you only/always update the local tables) is to add a table trigger to the local table. In this table code event, you can actually have it call some VBA code, and that VBA code could then update/insert to the linked MySQL table. Once again, then the two tables will automatic remain in sync.
The other possible would be to add a time + date stamp column to the tables (both on MySQL side, and on the Access side). You could then write some VBA code to sync up the tables. Such code is not too hard, but in a multi-user setting, this can become quite a challenge, since while you are syncing the data, other users might also update the MySQL tables and thus your sync routines might well miss some tables. Database sync software and this subject can fill a few books the size of medical texts, and is a VERY complex subject.
However, why not just always use linked tables to MySQL, and be done with any requirements to sync data? Access makes a great client to SQL server or MySQL. If you eliminate the local tables, then you eliminate the need to sync your data.
I have many users on my server, each user has their own database, with a set of tables. I also have a template database with a set of tables that I duplicate when someone signs up.
What I need to do is, if I make a change to the template database like; add a table, add a column, delete a column... I need to sync this database structure to the other databases.
Is there any way of doing this without writing a special script to check formats and make the appropriate changes?
For example i have 10 databases and they are the same. Only different data.
When i'm making some update in one database table(for example adding new collumn or changing/renaming it), it should affect others tables in all databases.
Can i make some view to make it easier or there is a way to do it automatically?
Thanks.
You can create a Trigger, which observe changes in the database structure.
See MySql trigger
I need to convert data that already exists in a MySQL database, to a SQL Server database.
The caveat here is that the old database was poorly designed, but the new one is in a proper 3N form. Does any one have any tips on how to go about doing this? I have SSMS 2005.
Can I use this to connect to the MySQL DB and create a DTS? Or do I need to use SSIS?
Do I need to script out the MySQL DB and alter every statement to "insert" into the SQL Server DB?
Has anyone gone through this before? Please HELP!!!
See this link. The idea is to add your MySQL database as a linked server in SQL Server via the MySQL ODBC driver. Then you can perform any operations you like on the MySQL database via SSMS, including copying data into SQL Server.
Congrats on moving up in the RDBMS world!
SSIS is designed to do this kind of thing. The first step is to map out manually where each piece of data will go in the new structure. So your old table had four fields, in your new structure fileds1 and 2 go to table a and field three and four go to table b, but you also need to have the autogenerated id from table a. Make notes as to where data types have changed and you may need to make adjustments or where you have required fileds where the data was not required before etc.
What I usually do is create staging tables. Put the data in the denormalized form in one staging table and then move to normalized staging tables and do the clean up there and add the new ids as soon as you have them to the staging tables. One thing you will need to do if you are moving from a denormalized database to a normalized one is that you will need to eliminate the duplicates from the parent tables before inserting them into the actual production tables. You may also need to do dataclean up as there may be required fileds in the new structure that were not required in the old or data converstion issues becasue of moving to better datatypes (for instance if you stored dates in the old database in varchar fields but properly move to datetime in the new db, you may have some records which don't have valid dates.
ANother issue you need to think about is how you will convert from the old record ids to the new ones.
This is not a an easy task, but it is doable if you take your time and work methodically. Now is not the time to try shortcuts.
What you need is an ETL (extract, transform, load) tool.
http://en.wikipedia.org/wiki/Extract,_transform,_load#Tools
I don't really know how far an 'ETL' tool will get you depending on the original and new database designs. In my career I've had to do more than a few data migrations and we usually always had to design a special utility which would update a fresh database with records from the old database, and yes we coded it complete with all the update/insert statements that would transform data.
I don't know how many tables your database has, but if they are not too many then you could consider going the grunt root. That's one technique that's guaranteed to work after all.
If you go to your database in SSMS and right-click, under tasks should be an option for "Import Data". You can try to use that. It's basically just a wizard that creates an SSIS package for you, which it can then either run for you automatically or which you can save and then alter as needed.
The big issue is how you need to transform the data. This goes into a lot of specifics which you don't include (and which are probably too numerous for you to include here anyway).
I'm certain that SSIS can handle whatever transformations you need to do to change it from the old format to the new. An alternative though would be to just import the tables into MS SQL as-is into staging tables, then use SQL code to transform the data into the 3NF tables. It's all a matter of what your most comfortable with. If you go the second route, then the import process that I mentioned above in SSMS could be used. It will even create the destination tables for you. Just be sure that you give them unique names, maybe prefixing them with "STG_" or something.
Davud mentioned linked servers. That's definitely another way that you can go (and got my upvote). Personally, I prefer to copy the tables over into MS SQL first since linked servers can sometimes have weirdness, especially when it comes to data types not mapping between different providers. Having the tables all in MS SQL will also probably be a bit faster and saves time if you have to rerun or correct portions of the data. As I said though, the linked server method would probably be fine too.
I have done this going the other direction and SSIS works fine, although I might have needed to use a script task to deal with slight data type weirdness. SSIS does ETL.
After dragging two tables in from one database, I switch to another and drag a table in. Now I get a message if I want to replace the connection string with the new one. I want tables from multiple databases in one DBML. Is this possible?
It is entirely possible to reference multiple databases within the same DBML, PROVIDED those databases reside on the same SQL Server.
In Visual Studio, right-click on the DBML, click "Open with..." , and select XML (Text) Editor with Encoding.
You will see your first table that you dragged in looks like this:
<Table Name="dbo.MyTable1fromMyDatabase1" Member="MyTable1fromMyDatabase1">
For your tables from other databases you wish to add, enter them like this:
<Table Name="MyDatabase2.dbo.MyTable1fromMyDatabase2" Member="MyTable1fromMyDatabase2">
This will work assuming the same login works for both databases, and your LINQ expressions can now query across both databases!
I don't believe that what you're looking for is possible, since the DataContext would then not have any easy way of resolving results from two separate databases.
If you're looking to create domain objects from two separate databases, then your best bet would be to have two separate DBML's, then use a bridge (GOF) or some other related design pattern to instantiate your domain objects.
Another option is to create a server link on on database that points to the other and make aliases to the remote tables from the "local" DB. I believe then you'd be able to reference them as if they were all in the same database.
We can also create a view that queries the table in the other database. We can select, insert and update this view, which will affect the table in the other database as well.