I am developing a web portal in Asp.Net. Primary target users will be of India Only. But in future I may target overseas users also. I want to know if I should use Sql Server Replication or not. Should I concern about "Replication" at initial stage or can I use it at later stages. Thanks in advance.
I don't think replication means what you think it means. Replication is a means of synchronizing multiple databases with data and it is most useful where databases need to be disconnected at times.
I don't think you need to be concerned about replication if you are developing a web app. If you will have multiple sites in the future, you can still have a single database hosted separately from any of the sites that all the localized sites reference and update independently.
Unless you will have multiple databases to be consolidated into a central db, NO, dont worry about it.
It will bring a whole world of hurt.
Related
So I am designing an WPF application that needs to support offline functionality.
That means I will have a local database that syncs with the master database when available. My questions is in regards to the integrity of the data sync. I want to verify that the changes that are being synced to the master database are actually being made in the master database. Vise versa as well. What ways should I approach this issue. It may be worth noting that I am by no means a DBA and have just trouble shooting experience when dealing with SQL.
Asuming you have SQL server as master and SQL express on WPF you need do several things and the best I can do is point you a tutorial
Tutorial: Synchronizing SQL Server and SQL Express
According to my system i have maintained two databases in LAN and online db.But i want to synchronize these two databases. I hope to do this things using microsoft sync frame work.
.http://msdn.microsoft.com/en-us/library/ee819079.aspx
Can i do sync local and online sql db using this? or any suitable method for do this.thank you
Sync Framework is designed for occasionally connected systems, eg. a laptop that can access the corporate network every other day and update its database, but needs to work when it has no corpnet access too. The pairing of Sync Framework is usually a central DB (SQL Server) and local embedded SQL Server Compact or SQL Express on the devices (laptops, phones, tablets etc).
IF the databases are always connected (eg. two DBs in two servers, with 24x7 connectivity between them, even if over Internet) then the appropriate technology is replication. Either Merge or Transactional. Theoretically replication also works when disconnect periods are expected, but Sync Framework is much better at it, and most importantly Sync Framework is not strongly dependent on DNS names as replication is (very important for occasionally connected systems).
Synchronizing the database is a vague term, you have to consider if you want a Master-Slave replication shcme or a Master-Master (the later being very difficult to achieve) and you have to consider what do you want replicated from the database. You also need to consider if more partners will be later added (more databases to 'synchronize'). And you have to be way more careful now about schema changes.
I am working on a database for a monitoring application, and I got all the business logic sorted out. It's all well and good, but one of the requirements is that the monitoring data is to be completely stand-alone.
I'm using a local database on my web-server to do some event handling and caching notifications. Since there is one event row per system on my monitor database, it's easy to just get the id and query the monitoring data if needed, and since this is something only my web server uses, integrity can be enforced externally. Querying is not an issue either, as all the relationships are one-to-one so it's very straight forward.
My problem comes with user administration. My original plan had it on yet another database (to meet the requirement of leaving the monitoring database alone), but I don't think I was thinking straight when I thought of that. I can get all the ids of the systems a user has access to easily enough, but how then can I efficiently pass that to a query on the other database? Is there a solution for this? Making a chain of ors seems like an ugly and buggy solution.
I assume this kind of problem isn't that uncommon? What do most developers do when they have to integrate different database servers? In any case, I am leaning towards just talking my employer into putting user administration data in the same database, but I want to know if this kind of thing can be done.
There are a few ways to accomplish what you are after:
Use concepts like linked servers (SQL Server - http://msdn.microsoft.com/en-us/library/ms188279.aspx)
Individual connection strings within your front end driving the database layer
Use things like replication to duplicate the data
Also, the concept of multiple databases on a single database server instance seems like it would not be violating your business requirements, and I investigate that as a starting point, with the details you have given.
We want to distribute / synchronize data from our Datawarehouse (MS SQL Server) to external customers (also MS SQL Server). The connection has to be secure, because we are dealing with trusted data. Transmission of data from our system to external client system must be via the http/https
In addition it is possible that the clients still run their systems with an older database schema, so already existing tables and columns should be transmitted and non existing ones should be ignored.
Its most likely that we will have large database updates and the updates have to arrive in almost real-time.
And it is definitely necessary that the data is stored in a client side datawarehouse / SQL database.
The whole process should also include good monitoring possibilities in case something goes wrong.
We started to develop our own .NET solution but I thought it should be almost a common problem to exchange data between different systems.
Does anybody know about an existing solution which we can adapt to our scenario?
Any help is appreciated!
The problem is so common that it has a dedicated component in SQL Server: Service Broker. Rather than start your own .Net thing and take care of the many problems (how are you gonna handle down time? Retries? duplicates? out of order delivery? authentication of non-domain joined computers? routing for machines that change names? service upgrades? transactional consistency, rollbacks? are you gonna use dtc?). You can look at the demo I gave to SQL connections to see how you can easily scale SSB to a throughput of well over 1000 msgs/sec (1k payload) on commodity hardware.
the only requirement is that all partitcipants must be at least SQL Server 2005 (no SSB in 2000).
Just use regular SQL connections over a secure VPN or an SSH tunnel. Should be very easy to setup for your networking guys.
For example, you can create a linked server. Then a SQL scheduled job could move the data:
truncate table targetserver.dbname.dbo.tablename
insert into targetserver.dbname.dbo.tablename
select a, b, c
from dbname.dbo.sourcetable
Since the linked server talks to your server over a VPN or SSH tunnel, all data is send encrypted over the internet.
SQL Server 2008 database design problem.
I'm defining the architecture for a service where site users would manage a large volume of data on multiple websites that they own (100MB average, 1GB maximum per site). I am considering whether to split the databases up such that the core site management tables (users, payments, contact details, login details, products etc) are held in one database, and the database relating to the customer's own websites is held in a separate database.
I am seeing a possible gain in that I can distribute the hardware architecture to provide more meat to the heavy lifting done in the websites database leaving the site management database in a more appropriate area. But I'm also conscious of losing the ability to directly relate the sites to the customers through a Foreign key (as far as I know this can't be done cross database?).
So, the question is two fold - in general terms should data in this sort of scenario be split out into multiple databases, or should it all be held in a single database?
If it is split into multiple, is there a recommended way to protect the integrity and security of the system at the database layer to ensure that there is a strong relationship between the two?
Thanks for your help.
This question and thus my answer may be close to the gray line of subjective, but at the least I think it would be common practice to separate out the 'admin' tables into their own db for what it sounds like you're doing. If you can tie a client to a specific server and db instance then by having separate db instances, it opens up some easy paths for adding servers to add clients. A single db would require you to monkey with various clustering approaches if you got too big.
[edit]Building in the idea early that each client gets it's own DB also just sets the tone for how you develop when it is easy to make structural and organizational changes. Discovering 2 yrs from now you need to do it will become a lot more painful. I've worked with split dbs plenty of times in the past and it really isn't hard to deal with as long as you can establish some idea of what the context is. Here it sounds like you already have the idea that the client is the context.
Just my two cents, like I said, you could be close to subjective on this one.
Single Database Pros
One database to maintain. One database to rule them all, and in the darkness - bind them...
One connection string
Can use Clustering
Separate Database per Customer Pros
Support for customization on per customer basis
Security: No chance of customers seeing each others data
Conclusion
The separate database approach would be valid if you plan to support per customer customization. I don't see the value if otherwise.
You can use link to connect the databases.
Your architecture is smart.
If you can't use a link, you can always replicate critical data to the website database from the users database in a read only mode.
concerning security - The best way is to have a service layer between ASP (or other web lang) and the database - so your databases will be pretty much isolated.
If you expect to have to split the databases across different hardware in the future because of heavy load, I'd say split it now. You can use replication to push copies of some of the tables from the main database to the site management databases. For now, you can run both databases on the same instance of SQL Server and later on, when you need to, you can move some of the databases to a separate machine as your volume grows.
Imagine we have infinitely fast computers, would you split your databases? Of course not. The only reason why we split them is to make it easy for us to scale out at some point. You don't really have any choice here, 100MB-1000MB per client is huge.