In SQL Server 2012, they have introduce the Contained Database. What is the real purpose of this feature? What drawbacks of previous versions has it fixed?
They are being developed to make migration of databases between systems easier (both your databases, and databases on SQL Azure that they need to move around to balance resources). Anything that has a dependency outside of the database is considered a risk, because it's extra scaffolding that has to go with the database - easy to forget, easy to get wrong, easy to fall out of sync.
For example, in Denali these issues are addressed:
Today when you move a database to another server, you also have to migrate all the SQL logins at the server level - this can be a pain especially when the SIDs get out of sync. With contained databases, database-level users that don't have a tie to a SQL Server login just come along for the ride when a database is backed up, detached, mirrored, replicated, etc. Nice and easy.
If you have a database with collation that differs from the server collation, you may find that you have collation conflicts when you join or perform other operations with #temp tables, because the #temp tables that get created will inherit the server collation, not the calling database. While you can get around that by specifying a COLLATE clause on every single column reference, with contained databases, #tempdb inherits the collation of the calling database, overriding the server collation.
THROW() can almost fall into this category as well - since you no longer have to use sys.messages to store custom messages. This is not as common as the above two issues, but it certainly does make migrating to a new server work better if there is no requirement to also keep sys.messages in sync. This is not restricted to contained databases, but it plays the same role.
For things that don't meet "containment" criteria, there is a DMV that can show you a list of things that will potentially break if you move them to another server. For example, a call to a three- or four-part name.
In future versions, there are other issues that will be addressed. For example:
SQL Server Agent is an external dependency. When you move a database to a different server, SQL Agent jobs that reference that database do not automatically move with the database, you have to determine which ones are affected and script them out yourself (it is not quite as simple as just bringing along msdb too). In a future version of SQL Server, I envision that either (a) each database will be able to have its own Agent, or (b) Agent will be moved to an OS-level architecture, where some translation layer tells you where the database is, instead of having to have Agent live on the same machine. The latter option can get complicated when we're talking about Azure, geo-disparate networks, etc.
Linked Servers are also an external dependency. This could be easily solved with database-level linked servers - especially since these are little more than synonym containers / pointers.
There are others, but those are the heavy hitters.
Related
We have a requirement where we will have to move data between different database instance on regular basis. (For e.g. some customers willing to pay more for the better performance). So this is not going to be one off.
The database tables has referential integrity. Is there a way in which this can be done without rewriting sql script (or some other method) every time we migrate customers data?
I came across this How to move data between multiple database's table while maintaining foreign-key relationships/referential integrity?. However it appears that we have write script every time we migrate data (please correct me if I misunderstood the answer on this thread).
Thanks
Edit:
Both servers are using SQL Server 2012 (same version). Its an Azure SQL Server database.
They are not necessarily linked (no firewall between them)
We are only transferring some data, not the whole database. This is only for certain customers who opted pay more.
The schema are exactly same in both databases.
Preyash - please see the documentation on the Split-Merge tool. The Split-Merge tool enables you do move data between databases, as you have described, based on a sharding key (e.g., customer ID). One modification that you will need for your application is to add a shard map (i.e., a database that understand the global state of which customers resides in which databases).
Have a look into Azure Data Sync. It is much more aligned with your requirements. But you may end up in having another SQL Azure DB to maintain a Hub. Azure data Sync follows hub-spoke pattern and will let you do all flexible directional syncs with a few minutes of syncing gap. It is more simple and can set it up very fast without any scripts and all as you wanted.
Is there any way to obscure the schema of a database on SQL Server?
If I have SQL Server Express installed on a client site, is there a way to obscure the schema and data so that someone else cannot come along and learn the schema in order to extract data out of it and into another product?
The best way to obscure your database schema is to not let it leave your servers.
Even if you encrypt the schema you still will have to provide the key somewhere, and if the client is determined to get it, they'll spend time and money to do so.
So you're better off either offering your product as service or making your client loyal by doing good job.
AFAIK, "no".
The best way to "lock down" your database is:
1) Install with appropriate roles and users (ideally, SQL roles and SQL users you create)
2) Explicitly restrict object permissions in SQL Server
3) Code your application to use SQL Server stored procedures (instead of raw T-SQL) as much as possible
4) Encrypt your stored procedures
Here's a good link on "SQL Server Best Practices" that might be of interest. It discusses security issues and a (relatively) new feature, "User Schema Separation":
http://msdn.microsoft.com/en-us/library/dd283095%28v=sql.100%29.aspx
This is a tricky one and may not even be 100% possible. However, there are a few tricks to setting it up:
Install a new named instance of SQL server with a custom SA account (both name and password). There is an installation method for SQL server call "Unattended Installation" which allows you to specify all the installation parameters for SQL server in an ini file and then run the install silently. Check out the documentation here: Unattended Installation of SQL Server 2008 r2
Create your database, tables, procedures, etc. with your magic SQL install script (use encrypted stored procs if you want, but they too are crackable)
Add/Verify the schema permissions for the custom SA account and Drop all schema permissions for all Administrator roles. The goal here is that no roles have any schema permissions to your database and only your custom SA user has permission (not assigned by role, but directly to the user).
There are several commercial applications that I know of that don't even tell you they are installing an instance of MS SQL express. They too will create their own named instance with a named SA account. I can't say I like that as a customer (as SQL takes a hit on the CPU and I don't want "secret" instances running on my workstation). But so long as you disclose this to your customers upfront, they may understand.
**Keep in mind a skilled DBA may have the knowledge to mess with system tables and what not to manually grant access to your database. These techniques really are just "obfuscation" and won't be 100% bullet proof.
As a side note: With the plethora of available 3rd party datalayers and webservice technologies, I think many companies are finding their database schema alone isn't so proprietary or valuable anymore. There was a time when the database schema alone could have represented hundreds of hours of coding. But today tools like EntityFramework, NHibernate, Linq-to-SQL, XPO, etc all create your database schema for you based on your software class definitions and in code attributes. So just seeing a DB table isn't really very valuable. Plus you might write a bunch of business logic, statistical analysis or other helper methods in your software that aren't in your database schema. In my opinion, this is where today's "value add" is found, in the business logic, analysis and reporting functionality of your software - not in the raw datatables.
This is also why another poster recommended obfuscating stored procedures, because these could be many times the work of the database schema itself if you have some nice analysis and reporting procedures written up. Its also what customer's would most likely want to customize for their own reporting needs. You may be inclined to have a policy that custom reporting can only be done by your company (hey, even the big guys like SAP are sticky with who can modify what).
There is a way, it's convoluted and ugly but it works.
You have a master table that acts as a lookup table for your other tables. This master table would look sort of like this:
id, guid, entityname, parent_id
then all of your table names and column names get renamed to be guids. after that you put an entry in the lookup table for each of them. When you want to select data you have to do so by pulling the guid's out of the lookup table by their entitynames which then give you the obscured table and column names.
There is a major software vendor out there that does something very similar to this, so it has been done before.
Can I store any custom tables in SharePoint's own database?
Is this supported behavior or not?
(I mean tables in MS SQL database, not SharePoint lists.)
If I can, how well does this play with backup/restore functionality?
What are possible caveats?
For anyone wondering why I'm asking: there's an app which is bound to SharePoint server and needs to store some purely relational internal information that doesn't make sense apart from that SharePoint instance. I would like to narrow down data storage to one place but I'm not sure if SharePoint likes its database being used for other purposes.
I'm using SharePoint 2007.
Is it possible? Sure. Should you? Nope.
The SharePoint content/configuration databases are subject to change with any update Microsoft releases, and any changes you make will very likely be destroyed, and if your farm depends on them, be left non-functional.
If you want to store purely relational data in a set of tables, just create another database. There's nothing stopping you from using the same SQL Server instance that houses your SharePoint content and/or configuration databases to store other relational databases as well.
Not a good idea: Support for changes to the databases used by Windows Sharepoint Services
...
Making any modification to the database schema
Adding tables to any of the databases
...
If an unsupported database modification is discovered during a support call, the customer must perform one of the following procedures at a minimum:
Perform a database restoration from the last known good backup that did not include the database modifications
Roll back all the database modifications
It is even worse than the above. It is likely that future upgrades will notice your changes to the content database schema and refuse to upgrade the database period.
I have been googling a lot and I couldn't find if this even exists or I'm asking for some magic =P
Ok, so here's the deal.
I need to have a way to create a "master-structured" database which will only contain the schemas, structures, tables, store procedures, udfs, etc, everything but real data in SQL SERVER 2005 (if this is available in 2008 let me know, I could try to convince my client to pay for it =P)
Then I want to have several "children" of that master db which implement those schemas, tables, etc but each one has different data.
So when I need to create a new stored procedure or something like that, I just create it on the master database (and of course it's available on its children).
Actually I have several different databases with the same schema and different data. But the problem is to maintain congruency between them. Everytime I create a script to create some SP or add some index or whatever, I have to execute it in every database, and sometimes I could miss one =P
So let's say you have a UNIVERSE (would be the master db) and the universe has SPACES (each one represented by a child db). So the application I'm working on needs to dynamically "clone" SPACES. To do that, we have to create a new database. Nowadays I'm creating a backup of the db being cloned, restoring it as a new one and truncate the tables.
I want to be able to create a new "child" of the "master" db, which will maintain the schemas and everything, but will start with empty data.
Hope it's clear... My english is not perfect, sorry about that =P
Thanks to all!
What you really need is to version-control your database schema.
See do-you-source-control-your-databases
If you use SQL Server, I would recommend dbGhost - not expensive and does a great job of:
synchronizing 2 databases
diff-ing 2 databases
creating a database from a set of scripts (I would recommend this version).
batch support, so that you can upgrade all your databases using a single batch
You can use this infrastructure for both:
rolling development versions to test, integration and production systems
rolling your 'updated' system to multiple production deployments (especially in a hosted environment)
I would write my changes as a sql file and use OSQL or SQLCMD via a batchfile to ensure that I repeatedly executed on all the databases without thinking about it.
As an alternative I would use the VisualStudio Database Pro tools or RedGate SQL compare tools to compare and propogate the changes.
There are kludges, but the mainstream way to handle this is still to use Source Code Control (with all its other attendant benefits.) And SQL Server is increasingly SCC friendly.
Also, for many (most robust) sites it's a per-server issue as much as a per-database issue.
You can put things in master like SPs and call them from anywhere. As far as other objects like tables, you can put them in model and new databases will get them when you create a new database.
However, in order to get new tables to simply pop up in the child databases after being added to the parent, nothing.
It would be possible to create something to look through the databases and script them from a template database, and there are also commercial tools which can help discover differences between databases. You could also have a DDL trigger in the "master" database which went out and did this when you created a new table.
If you kept a nice SPACES template, you could script it out (without data) and create the new database - so there would be no need to TRUNCATE. You can script it out from SQL or an external tool.
Little trivia here. The mssqlsystemresource database works as you describe: is defined once and 'appears' in every database as the special sys schema. Unfortunately the special 'magic' needed to get this working is not available to the user databases. You'll have to use deployment techniques to keep your schema in synk. That is, apply the changes to every database as the other answers already suggested.
In theory, you could put a trigger on your UNIVERSE.sysobjects table (assuming SQL Server), and then you could enumerate master.dbo.sysdatabases to find all the child databases. If you have a special table that indicates it's a child database, you can reference child.dbo.sysobjects to find it.
Make no mistake, it would be difficult to implement. But it's one way you could do it.
Bear in mind here, I am not an Access guru. I am proficient with SQL Server and .Net framework. Here is my situation:
A very large MS Access 2007 application was built for my company by a contractor.
The application has been split into two tiers BY ACCESS; there is a front end portion that holds all of the Ms Access forms, and then on the back end part, which are access tables, queries, etc., that is stored on a computer on the network.
Well, of course, there is a need to convert the data storage portion to SQL Server 2005 while keeping all of these GUI forms which were built in Ms Access. This is where I come in.
I have read a little, and have found that you can link the forms or maybe even the access tables to SQL Server tables, but I am still very unsure on what exactly can be done and how to do it.
Has anyone done this? Please comment on any capabilities, limitations, considerations about such an undertaking. Thanks!
Do not use the upsizing wizard from Access:
First, it won't work with SQL Server 2008.
Second, there is a much better tool for the job:
SSMA, the SQL Server Migration Assistant for Access which is provided for free by Microsoft.
It will do a lot for you:
move your data from Access to SQL Server
automatically link the tables back into Access
give you lots of information about potential issues due to differences in the two databases
keeps track of the changes so you can keep the two synchronised over time until your migration is complete.
I wrote a blog entry about it recently.
You have a couple of options, the upsizing wizard does a decent(ish) job of moving structure and data from access to Sql. You can then setup linked tables so your application 'should' work pretty much as it does now. Unfortunately the Sql dialect used by Access is different from Sql Server, so if there are any 'raw sql' statements in the code they may need to be changed.
As you've linked to tables though all the other features of Access, the QBE, forms and so on should work as expected. That's the simplest and probably best approach.
Another way of approaching the issue would be to migrate the data as above, and then rather than using linked tables, make use of ADO from within access. That approach is kind of famaliar if you're used to other languages/dev environments, but it's the wrong approach. Access comes with loads of built in stuff that makes working with data really easy, if you go back to use ADO/Sql you then lose many of those benefits.
I suggest start on a small part of the application - non essential data, and migrate a few tables and see how it goes. Of course you back everything up first.
Good luck
Others have suggested upsizing the Jet back end to SQL Server and linking via ODBC. In an ideal world, the app will work beautifully without needing to change anything.
In the real world, you'll find that some of your front-end objects that were engineered to be efficient and fast with a Jet back end don't actually work very well with a server database. Sometimes Jet guesses wrong and sends something really inefficient to the server. This is particular the case with mass updates of records -- in order not to hog server resources (a good thing), Jet will send a single UPDATE statement for each record (which is a bad thing for your app, since it's much, much slower than a single UPDATE statement).
What you have to do is evaluate everything in your app after you've upsized it and where there are performance problems, move some of the logic to the server. This means you may create a few server-side views, or you may use passthrough queries (to hand off the whole SQL statement to SQL Server and not letting Jet worry about it), or you may need to create stored procedures on the server (especially for update operations).
But in general, it's actually quite safe to assume that most of it will work fine without change. It likely won't be as fast as the old Access/Jet app, but that's where you can use SQL Profiler to figure out what the holdup is and re-architect things to be more efficient with the SQL Server back end.
If the Access app was already efficiently designed (e.g., forms are never bound to full tables, but instead to recordsources with restrictive WHERE clauses returning only 1 or a few records), then it will likely work pretty well. On the other hand, if it uses a lot of the bad practices seen in the Access sample databases and templates, you could run into huge problems.
It's my opinion that every Access/Jet app should be designed from the beginning with the idea that someday it will be upsized to use a server back end. This means that the Access/Jet app will actually be quite efficient and speedy, but also that when you do upsize, it will cause a minimum of pain.
This is your lowest-cost option. You're going to want to set up an ODBC connection for your Access clients pointing to your SQL Server. You can then use the (I think) "Import" option to "link" a table to the SQL Server via the ODBC source. Migrate your data from the Access tables to SQL Server, and you have your data on SQL Server in a form you can manage and back up. Important, queries can then be written on SQL Server as views and presented to the Access db as linked tables as well.
Linked Access tables work fine but I've only used them with ODBC and other databases (Firebird, MySQL, Sqlite3). Information on primary or foreign keys wasn't passing through. There were also problems with datatype interpretation: a date in MySQL is not the same thing as in Access VBA. I guess these problems aren't nearly as bad when using SQL Server.
Important Point: If you link the tables in Access to SQL Server, then EVERY table must have a Primary Key defined (Contractor? Access? Experience says that probably some tables don't have PKs). If a PK is not defined, then the Access forms will not be able to update and insert rows, rendering the tables effectively read-only.
Take a look at this Access to SQL Server migration tool. It might be one of the few, if not the ONLY, true peer-to-peer or server-to-server migration tools running as a pure Web Application. It uses mostly ASP 3.0, XML, the File System Object, the Data Dictionary Object, ADO, ADO Extensions (ADOX), the Dictionary Scripting Objects and a few other neat Microsoft techniques and technologies. If you have the Source Access Table on one server and the destination SQL Server on another server or even the same server and you want to run this as a Web Internet solution this is the product for you. This example discusses the VPASP Shopping Cart, but it will work for ANY version of Access and for ANY version of SQL Server from SQL 2000 to SQL 2008.
I am finishing up development for a generic Database Upgrade Conversion process involving the automated conversion of Access Table, View and Index Structures in a VPASP Shopping or any other Access System to their SQL Server 2005/2008 equivalents. It runs right from your server without the need for any outside assistance from external staff or consultants.
After creating a clone of your Access tables, indexes and views in SQL Server this data migration routine will selectively migrate all the data from your Access tables into your new SQL Server 2005/2008 tables without having to give out either your actual Access Database or the Table Contents or your passwords to anyone.
Here is the Reverse Engineering part of the process running against a system with almost 200 tables and almost 300 indexes and Views which is being done as a system acceptance test. Still a work in progress, but the core pieces are in place.
http://www.21stcenturyecommerce.com/SQLDDL/ViewDBTables.asp
I do the automated reverse engineering of the Access Table DDLs (Data Definition Language) and convert them into SQL equivalent DDL Statements, because table structures and even extra tables might be slightly different for every VPASP customer and for every version of VP-ASP out there.
I am finishing the actual data conversion routine which would migrate the data from Access to SQL Server after these new SQL Tables have been created including any views or indexes. It is written entirely in ASP, with VB Scripting, the File System Object (FSO), the Dictionary Object, XML, DHTML, JavaScript right now and runs pretty quickly as you will see against a SQL Server 2008 Database just for the sake of an example.
It takes perhaps 15-20 seconds to reverse engineer almost 500 different database objects. There might be a total of over 2,000 columns involved in this example for the 170 tables and 270 indexes involved.
I have even come up with a way for you to run both VPASP systems in parallel using 2 different database connection files on the same server just to be sure that orders entered on the Access System and the SQL Server system produce the same results before actual cutover to production.
John (a/k/a The SQL Dude)
sales#designersyles.biz
(This is a VP-ASP Demo Site)
Here is a technique I've heard one developer speak on. This is if you really want something like a Client-Server application.
Create .mdb/.mde frontend files distributed to each user (You'll see why).
For every table they need to perform an CRUD, have a local copy in the file in #1.
The forms stay linked to the local tables.
Write VBA code to handle the CRUD from the local tables to the SQL Server database.
Reports can be based off of temp tables created from the SQL Server (Won't be able to create temp tables in mde file I don't think).
Once you decide how you want to do this with a single form, it is not too difficult to apply the same technique to the rest. The nice thing about working with the form on a local table is you can keep a lot of the existing functionality as the existing application (Which is why they used and continue to use Access I hope). You just need to address getting data back and forth to the SQL Server.
You can continue to have linked tables, and then gradually phase them out with this technique as time and performance needs dictate.
Since each user has their own local file, they can work on their local copy of the data. Only the minimum required to do their task should ever be copied locally. Example: if they are updating a single record, the table would only have that record. When a user adds a new record, you would notice that the ID field for the record is Null, so an insert statement is needed.
I guess the local table acts like a dataset in .NET? I'm sure in some way this is an imperfect analogy.