I have a split database and I have duplicated front-end file to make multiple copies for different users. Every-time a change is made on one front-end form, I want the other forms in other front-ends to always drop changes. How can I trap this write conflict to always drop changes maybe through VBA if possible?
Not quite sure what you mean by "drop changes" - the frontend should never be redesigned during normal use.
You must distribute a new copy of the frontend to the users.
A smooth and proven method using a shortcut and a script is described in my article:
Deploy and update a Microsoft Access application with one click
(If you don't have an account, browse for the link: Read the full article)
Edit:
If it is the data that is updated by several users, and you update via VBA, you may study another of my articles:
Handle concurrent update conflicts in Access silently
Though simple to use, the code is a bit too much to post here. It is also on GitHub:
VBA.ConcurrencyUpdates
Is there a way to update the Liferay's site page's friendly name through a SQL script?
We generally do this in the control panel through admin user.
While #steven35's answer might do the job, you're hitting a pet peeve of mine. On a different level, you're doing it right if you're doing it on the Control Panel, or through the API and you should not think about a way to ever write to Liferay's database. It might work for the moment, but it might also fail in unforeseen ways - sometimes long after your update.
There have been enough samples for this to happen. If you're changing data while Liferay is running, the cache will not be updated. In case these values are also indexed in the search index, they won't be updated there and random later uses might not find the correct page without you reindexing everything. The same value might be stored somewhere else - or translated. Numerous conditions can fail - and there's always one condition more than you expect and cater for. That one condition might break your neck.
Granted, the friendly name of a page might not fall into the most complex of these cases, but just don't get into the habit of writing to Liferay's database. Or, if you do, don't complain about future upgrades failing or requiring extra work, because the database contains values that the API didn't expect. The problem is that during the next upgrade (if you do it in - say - one year) you'll long have forgotten that you manually changed data in the database and blame Liferay for problems during your upgrade.
Changing data is exactly what the UI and the API are for.
Friendly urls are stored in LayoutFriendlyURL.friendlyURL in your Liferay database so the following query should work
UPDATE "yourdatabase"."LayoutFriendlyURL" SET "friendlyURL"="/newurl" WHERE "layoutFriendlyURLId"=12345;
You will also need to update the Layout table accordingly to match the new friendly url.
I have just started using RavenDB on a personal project and so far inserting, updating and querying have all been very easy to implement. However, I have come across a situation where I need a GetOrCreate method and I'm wondering what the best way to achieve this is.
Specifically I am integrating with OpenID and once authentication has taken place the user is redirected to my site. At this point I'd either like to retrieve their user record from Raven (by querying on the ClaimsIdentifier property) or create a new record. The user's ID is currently being set by Raven.
Obviously I can write this in two statements but without some sort of transaction around the select and the create I could potentially end up with two user records in the database with the same claims identifier.
Is there anyway to achieve this kind of functionality? Possibly even more importantly is do you think I'm going down the wrong path. I'm assuming even if I could create a transaction it would make scaling out to multiple servers difficult and in anycase could add a performance bottle-neck.
Would a better approach be to have the Query and Create operations as separate statements and check for duplicates when the user is retrieved and merge at that point. Or do something similar but on a scheduled task?
I can't help but feel I'm missing something obvious here so any advice on this problem would be greatly appreciated.
Note: while scaling out to multiple servers may seem unnessecary for a personal project, I'm using it as an evaluation of Raven before using it in work.
Dan, although RavenDB has support for transactions, I wouldn't go that way in your case. Instead, you could just use the users ClaimsIdentifier as the user documents id, because they are granted to be unique.
Alternatively, you can also stay with user ids being generated by Raven (HiLo btw) and use the new UniqueConstraintsBundle, which lets you attribute certain properties to be unique. Internally it will create an additional document that has the value of your unique property as its id.
I have got a database of ms-sql server 2005 named mydb, which is being accessed by 7 applications from different location.
i have created its copy named mydbNew and tuned it by applying primary keys, indexes and changing queries in stored procedure.
now i wants to replace old db "mydb" from new db "mydbnew"
please tell me what is the best approach to do it. i though to do changes in web.config but all those application accessing it are not accessible to me, cant go for it.
please provide me experts opinion, so that i can do replace database in minimum time without affecting other db and all its application.
my meaning of saying replace old db by new db is that i wants to rename old db "mydb" to "mydbold" and then wants to remname my new db "mydbnew" to "mydb"
thanks
Your plan will work but it does carry a high risk, especially since I'm assuming this is a system that has users actively changing data, which means your copy won't have the same level of updated content in it unless you do a cut right before go-live. Your best bet is to migrate your changes carefully into the live system during a low traffic / maintenance period and extensively test it once your done. Prior to doing this, or the method you mentioned previously, backup everything.
All of the changes you described above can be made to an online database without the need to actually bring it down. However, some of those activities will change the way in which the data is affected by certain actions (changes to stored procs), that means that during the transition the behaviour of the system or systems may be unpredicatable and therefore you should either complete this update at a low point in day to day operations or take it down for a maintenance window.
Sql Server comes with a function to make a script file out of you database, you can also do this manually but clicking on the object you want to script and selecting the Script -> CREATE option. Depending on the amount of changes you have to make it may be worthwhile to script your whole new database (By clicking on the new database and selecting Tasks -> Generate Scripts... and selecting the items needed).
If you want to just script out the new things you need to add individually then you simply click on the object you want to script, select the Script <object> as -> then select DROP and CREATE to if you want to kill the original version (like replacing a stored proc) or select CREATE to if your adding new stuff.
Once you have all the things you want to add/update as a script your then ready to execute that against the new database. This would be the part where you backup everything. Once your happy everything is backed up and the system is in maintenance or a low traqffic period, you execute the script. There may be a few problems when you do this, you will need to fix these as quickly as possible (usually mostly just 'already exisits' errors, thats why drop and create scripts are good) and if anything goes really wrong restore your backups and try again (after figuring out what happened and how to fix it).
Make no mistake if you have a lot of changes to make this could be a long process, or it could take mere minutes, you just need to adapt if things go wrong and be sure to cover yourself with backups/extensive prayer. Good Luck!
I'm using SQL-Server 2008 with Visual Studio Database Edition.
With this setup, keeping your schema in sync is very easy. Basically, there's a 'compare schema' tool that allow me to sync the schema of two databases and/or a database schema with a source-controlled creation script folder.
However, the situation is less clear when it comes to data, which can be of three different kind :
static data referenced in the code. typical example : my users can change their setting, and their configuration is stored on the server. However, there's a system-wide default value for each setting that is used in case the user didn't override it. The table containing those default settings grows as more options are added to the program. This means that when a new feature/option is checked in, the system-wide default setting is usually created in the database as well.
static data. eg. a product list populating a dropdown list. The program doesn't rely on the existence of a specific product in the list to work. This can be for example a list of unicode-encoded products that should be deployed in production when the new "unicode version" of the program is deployed.
other data, ie everything else (logs, user accounts, user data, etc.)
It seems obvious to me that my third item shouldn't be source-controlled (of course, it should be backuped on a regular basis)
But regarding the static data, I'm wondering what to do.
Should I append the insert scripts to the creation scripts? or maybe use separate scripts?
How do I (as a developer) warn the people doing the deployment that they should execute an insert statement ?
Should I differentiate my two kind of data? (the first one being usually created by a dev, while the second one is usually created by a non-dev)
How do you manage your DB static data ?
I have explained the technique I used in my blog Version Control and Your Database. I use database metadata (in this case SQL Server extended properties) to store the deployed application version. I only have scripts that upgrade from version to version. At startup the application reads the deployed version from the database metadata (lack of metadata is interpreted as version 0, ie. nothing is yet deployed). For each version there is an application function that upgrades to the next version. Usually this function runs an internal resource T-SQL script that does the upgrade, but it can be something else, like deploying a CLR assembly in the database.
There is no script to deploy the 'current' database schema. New installments iterate trough all intermediate versions, from version 1 to current version.
There are several advantages I enjoy by this technique:
Is easy for me to test a new version. I have a backup of the previous version, I apply the upgrade script, then I can revert to the previous version, change the script, try again, until I'm happy with the result.
My application can be deployed on top of any previous version. Various clients have various deployed version. When they upgrade, my application supports upgrade from any previous version.
There is no difference between a fresh install and an upgrade, it runs the same code, so I have fewer code paths to maintain and test.
There is no difference between DML and DDL changes (your original question). they all treated the same way, as script run to change from one version to next. When I need to make a change like you describe (change a default), I actually increase the schema version even if no other DDL change occurs. So at version 5.1 the default was 'foo', in 5.2 the default is 'bar' and that is the only difference between the two versions, and the 'upgrade' step is simply an UPDATE statement (followed of course by the version metadata change, ie. sp_updateextendedproperty).
All changes are in source control, part of the application sources (T-SQL scripts mostly).
I can easily get to any previous schema version, eg. to repro a customer complaint, simply by running the upgrade sequence and stopping at the version I'm interested in.
This approach saved my skin a number of times and I'm a true believer now. There is only one disadvantage: there is no obvious place to look in source to find 'what is the current form of procedure foo?'. Because the latest version of foo might have been upgraded 2 or 3 versions ago and it wasn't changed since, I need to look at the upgrade script for that version. I usually resort to just looking into the database and see what's in there, rather than searching through the upgrade scripts.
One final note: this is actually not my invention. This is modeled exactly after how SQL Server itself upgrades the database metadata (mssqlsystemresource).
If you are changing the static data (adding a new item to the table that is used to generate a drop-down list) then the insert should be in source control and deployed with the rest of the code. This is especially true if the insert is needed for the rest of the code to work. Otherwise, this step may be forgotten when the code is deployed and not so nice things happen.
If static data comes from another source (such as an import of the current airport codes in the US), then you may simply need to run an already documented import process. The import process itself should be in source control (we do this with all our SSIS packages), but the data need not be.
Here at Red Gate we recently added a feature to SQL Data Compare allowing static data to be stored as DML (one .sql file for each table) alongside the schema DDL that is currently supported by SQL Compare.
To understand how this works, here is a diagram that explains how it works.
The idea is that when you want to push changes to your target server, you do a comparison using the scripts as the source data source, which generates the necessary DML synchronization script to update the target. This means you don't have to assume that the target is being recreated from scratch each time. In time we hope to support static data in our upcoming SQL Source Control tool.
David Atkinson, Product Manager, Red Gate Software
I have come across this when developing CMS systems.
I went with appending the static data (the stuff referenced in the code) to the database creation scripts, then a separate script to add in any 'initialisation data' (like countries, initial product population etc).
For the first two steps, you could consider using an intermediate format (ie XML) for the data, then using a home grown tool, or something like CodeSmith to generate the SQL, and possible source files as well, if (for example) you have lookup tables which relate to enumerations used in the code - this helps enforce consistency.
This has another benefit that if the schema changes, in many cases you don't have to regenerate all your INSERT statements - you just change the tool.
I really like your distinction of the three types of data.
I agree for the third.
In our application, we try to avoid putting in the database the first, because it is duplicated (as it has to be in the code, the database is a duplicate). A secondary benefice is that we need no join or query to get access to that value from the code, so this speed things up.
If there is additional information that we would like to have in the database, for example if it can be changed per customer site, we separate the two. Other tables can still reference that data (either by index ex: 0, 1, 2, 3 or by code ex: EMPTY, SIMPLE, DOUBLE, ALL).
For the second, the scripts should be in source-control. We separate them from the structure (I think they typically are replaced as time goes, while the structures keeps adding deltas).
How do I (as a developer) warn the people doing the deployment that they should execute an insert statement ?
We have a complete procedure for that, and a readme coming with each release, with scripts and so on...
First off, I have never used Visual Studio Database Edition. You are blessed (or cursed) with whatever tools this utility gives you. Hopefully that includes a lot of flexibility.
I don't know that I'd make that big a difference between your type 1 and type 2 static data. Both are sets of data that are defined once and then never updated, barring subsequent releases and updates, right? In which case the main difference is in how or why the data is as it is, and not so much in how it is stored or initialized. (Unless the data is environment-specific, as in "A" for development, "B" for Production. This would be "type 4" data, and I shall cheerfully ignore it in this post, because I've solved it useing SQLCMD variables and they give me a headache.)
First, I would make a script to create all the tables in the database--preferably only one script, otherwise you can have a LOT of scripts lying about (and find-and-replace when renaming columns becomes very awkward). Then, I would make a script to populate the static data in these tables. This script could be appended to the end of the table script, or made it's own script, or even made one script per table, a good idea if you have hundreds or thousands of rows to load. (Some folks make a csv file and then issue a BULK INSERT on it, but I'd avoid that is it just gives you two files and a complex process [configuring drive mappings on deployment] to manage.)
The key thing to remember is that data (as stored in databases) can and will change over time. Rarely (if ever!) will you have the luxury of deleting your Production database and replacing it with a fresh, shiny, new one devoid of all that crufty data from the past umpteen years. Databases are all about changes over time, and that's where scripts come into their own. You start with the scripts to create the database, and then over time you add scripts that modify the database as changes come along -- and this applies to your static data (of any type) as well.
(Ultimately, my methodology is analogous to accounting: you have accounts, and as changes come in you adjust the accounts with journal entries. If you find you made a mistake, you never go back and modify your entries, you just make a subsequent entries to reverse and fix them. It's only an analogy, but the logic is sound.)
The solution I use is to have create and change scripts in source control, coupled with version information stored in the database.
Then, I have an install wizard that can detect whether it needs to create or update the db - the update process is managed by picking appropriate scripts based on the stored version information in the database.
See this thread's answer. Static data from your first two points should be in source control, IMHO.
Edit: *new
all-in-one or a separate script? it does not really matter as long as you (dev team) agree with your deployment team. I prefer to separate files, but I still can always create all-in-one.sql from those in the proper order [Logins, Roles, Users; Tables; Views; Stored Procedures; UDFs; Static Data; (Audit Tables, Audit Triggers)]
how do you make sure they execute it: well, make it another step in your application/database deployment documentation. If you roll out application which really needs specific (new) static data in the database, then you might want to perform a DB version check in your application. and you update the DB_VERSION to your new release number as part of that script. Then your application on a start-up should check it and report an error if the new DB version is required.
dev and non-dev static data: I have never seen this case actually. More often there is real static data, which you might call "dev", which is major configuration, ISO static data etc. The other type is default lookup data, which is there for users to start with, but they might add more. The mechanism to INSERT these data might be different, because you need to ensure you do not destoy (power-)user-created data.