So I have two SQL Servers at the moment, both 2012 and both running separate systems.
One of these servers runs on a collation of latin1_general_bin and the other runs with latin1_general_ci_as, ideally I'd like to shut one of these servers off and move all the systems to one place.
I know this can be done technically, however I was wondering if this was a good idea? Will I be causing myself more problems down the line?
Both databases are transactional based and are defined by external parties so cannot have their collation changed. If I were as to do this, would it be better to have the server collation set as latin1_general_bin or latin1_general_ci_as? I'm thinking that the case sensitive option would be better as queries would still run against case insensitive databases whilst case insensitive queries would need to be carefully managed
There should be no problem using databases with different collations on one server. One of our external vendors also provides a database with different collation and this has been working without issues since SQL Server 2000. However, you will have to explicitly specify the collation (or use collation database_default when you want to join tables from the different databases. From my own experience, that can have quite a performance impact. You also need to be careful when using SELECT INTO when creating a new table as this can result in mixed collation in a database or table.
Yes, SQL Server keeps the collation neatly separated with the databases. But there is a big flaw, which caused severe problems with one of our customers:
The temp table (CREATE TABLE #Tbl ...) uses the server's default collation if you do not specify the collation explicitly.
In one of our projects, especially with quite old stored Procedures created with SQL Server 2000, there was heavy usage of temp tables to store intermediate results.
The customer ran into crazy errors and it took a hell of a lot of time to track this down. He did not want to change his server (due to other databases running there). So we changed the database to his collation. After this some of our upgrade scripts did not run anymore... It ended with all databases changed to the same collation and the installation of another instance of SQL Server.
Which collation is the best for you? I don't know... This depends on your needs. Are you dealing with diacritic characters a lot (look at "_as"), do you want "test" to be equal with "TeSt" (look at "_ci")
Related
I have several databases on a SQL Server instance. I have certain queries that extract information simultaneously these databases. It turns out that after restoring of one of the databases (but that came from another server), these queries gives a COLLATION error. I realized then that this "new" database has a different COLLATION, so that forces me to use the COLLATE for each respective column in these queries. The problem is I have many queries and it would not be practical to make this change on all. I have way to change Database COLLATION, as well as all needed columns? I already tried to change the Database but it seems that columns COLLATION remain the same...
If the collation for individual columns are not set to Database default, you should change them one by one.
I have one question, I was trying to find more information on the internet but, I'm still not sure about it.
If I have a SQL Server instance with the following default Collation example "Modern_Spanish_CI_AS" and I also have a restored databse with different collation example "Latin1_General_CI_AS".
What collation SQL Server will use? by default the Modern_Spanish... or it will use from database Latin1_General?
In the follwing link explains something about it
Setting and Changing the Server Collation
Thanks!
It will use the Latin1_General_CI_AS collation, as that's what's set in the database itself.
For clarification, whatever's set in the database will override the "default" collation for the server. The default collation is basically only used when you create a brand new database.
Changing the default collation at the server level has no effect on existing databases, you would have to change each collation individually, though that in itself will probably cause you cascading issues with any other database level objects you've created, such as stored procedures, constraints and even any dynamic SQL you're executing against the database from 3rd party applications.
SQL Server collations can be set at various levels: server, database, column, expession. If you do not set a collation at a lower level it is inherited from the level above. E.g. when creating a database the database collation will be the server's collation unless you explicitly set a collation for the DB.
And many collations will work together fine. Occasionally there can be difficulties, often of the nature of sort order being unexpected. I do not know for sure but I would expect the 2 you specify to be compatible.
So yes, your DB will (almost certainly) restore with the Latin1_General_CI_AS collation and almost certainly be fine. There is a list of compatible collations which Google should be able to help you find.
Assume SQL Server 2005+.
Part A:
What is the canonical way to query from the system/internal/meta/whatever tables/views (sorry, not a database ninja) for any user table or column names that use SQL Server keywords (like case)?
I don't mind maintaining the list of keywords if that's not query-able, as it only changes with versions of SQL Server supported (right?).
Looking at available views in SQL Server 2005, I can easily enough query this information from INFORMATION_SCHEMA.COLUMNS and INFORMATION_SCHEMA.TABLES, but I want to be sure it's from the best possible location for future-proofing.
Part B:
Is it possible to get the list of keywords via query?
UPDATE: While a useful concept, I'm specifically not interested in escaping the column/table/etc names in question because I'm hoping to write a tool that will check for tables/columns/etc that share names with keywords and provide useful warnings to developers. The tool would be used during code reviews at my office to point out that the developer might want to consider renaming the entity. (Or hopefully by the developer before code reviews for their own good!) I may even set it up for use with continuous integration in my build scripts, but that's only a thought for the future.
You should properly quote the names used. If you generate code, use the built-in QUOTENAME function. Don't build a list of known keywords, instead quote every name used for every object, including database name, schema name and object name. Also make sure you always adhere to the correct case of the objects involved. As a best practice, develop on a case sensitive collation server instance. Developing code on case insensitive server collation (default) can lead to embarasing failures on production when deployed on case sensitive collation servers.
For Part A
Personally I would go for sys.columns and sys.objects actually. INFORMATION_SCHEMA views are also good, and they're 'portable' in theory, I'm just so much more used to the SQL specific ones though. I choose sys.objects vs. sys.tables because it covers more (eg. views). I would suggest you also cover table valued functions, table valued parameter types (in 2008 only) and temporary #tables and table #variables declared inside stored procedures. That would leave out only temp #tables and table #variables declared in batches sent by clients, but those are basically in client code only.
A: Just use brackets around your identifier.
select [procedure].[case] from [procedure]
B: I'm not sure if you can query for them, but there is a MSDN page about it.
If you need these programmatically, I suggest you insert them all into a table for your own uses.
Why do you need to know the list of keywords? a: they don't change very often, and b: for any regular code (I'm excluding things like "sql server management studio") you can just use square brackets:
SELECT [table].[column], [table].[join]
FROM [table]
How to create a dynamic SQL statement, that will update any table given as one of parameter. Here I believe, i couldn't use "Set Column1 = Value ....." as the columns will differ according to the table.
This is an extremely poor idea. You can create massive havoc with your database doing such a thing. I can't imagine any dba who would allow it. You need to know the specifics of a table to insert into it properly, you need to be aware of what fields are required and what fields have default values. You need to know what kind of information and data types should be in each field so that you do not send bad data to the database. One proc that does all cannot properly check these things and certainly can't ever be properly tested. Further it means permissions must be at the table level which is a poor choice for internal security as well as for SQL injection attacks.
Could you provide more context? Are you executing arbitrary SQL statements from within scripts, such as Perl, PHP, or Python? Are you just trying to get a command-line .sql script working? What database server are you working on?
The solution can vary widely depending on your situation.
I'm looking for a way to validate the SQL schema on a production DB after updating an application version. If the application does not match the DB schema version, there should be a way to warn the user and list the changes needed.
Is there a tool or a framework (to use programatically) with built-in features to do that?
Or is there some simple algorithm to run this comparison?
Update: Red gate lists "from $395". Anything free? Or more foolproof than just keeping the version number?
Try this SQL.
- Run it against each database.
- Save the output to text files.
- Diff the text files.
/* get list of objects in the database */
SELECT name,
type
FROM sysobjects
ORDER BY type, name
/* get list of columns in each table / parameters for each stored procedure */
SELECT so.name,
so.type,
sc.name,
sc.number,
sc.colid,
sc.status,
sc.type,
sc.length,
sc.usertype ,
sc.scale
FROM sysobjects so ,
syscolumns sc
WHERE so.id = sc.id
ORDER BY so.type, so.name, sc.name
/* get definition of each stored procedure */
SELECT so.name,
so.type,
sc.number,
sc.text
FROM sysobjects so ,
syscomments sc
WHERE so.id = sc.id
ORDER BY so.type, so.name, sc.number
I hope I can help - this is the article I suggest reading:
Compare SQL Server database schemas automatically
It describes how you can automate the SQL Server schema comparison and synchronization process using T-SQL, SSMS or a third party tool.
You can do it programatically by looking in the data dictionary (sys.objects, sys.columns etc.) of both databases and comparing them. However, there are also tools like Redgate SQL Compare Pro that do this for you. I have specified this as a part of the tooling for QA on data warehouse systems on a few occasions now, including the one I am currently working on. On my current gig this was no problem at all, as the DBA's here were already using it.
The basic methodology for using these tools is to maintain a reference script that builds the database and keep this in version control. Run the script into a scratch database and compare it with your target to see the differences. It will also generate patch scripts if you feel so inclined.
As far as I know there's nothing free that does this unless you feel like writing your own. Redgate is cheap enough that it might as well be free. Even as a QA tool to prove that the production DB is not in the configuration it was meant to be it will save you its purchase price after one incident.
You can now use my SQL Admin Studio for free to run a Schema Compare, Data Compare and Sync the Changes. No longer requires a license key download from here http://www.simego.com/Products/SQL-Admin-Studio
Also works against SQL Azure.
[UPDATE: Yes I am the Author of the above program, as it's now Free I just wanted to Share it with the community]
If you are looking for a tool that can compare two databases and show you the difference Red Gate makes SQL Compare
You didn't mention which RDMBS you're using: if the INFORMATION SCHEMA views are available in your RDBMS, and if you can reference both schemas from the same host, you can query the INFORMATION SCHEMA views to identify differences in:
-tables
-columns
-column types
-constraints (e.g. primary keys, unique constraints, foreign keys, etc)
I've written a set of queries for exactly this purpose on SQL Server for a past job - it worked well to identify differences. Many of the queries were using LEFT JOINs with IS NULL to check for the absence of expected items, others were comparing things like column types or constraint names.
It's a little tedious, but its possible.
I found this small and free tool that fits most of my needs.
http://www.wintestgear.com/products/MSSQLSchemaDiff/MSSQLSchemaDiff.html
It's very basic but it shows you the schema differences of two databases.
It doesn't have any fancy stuff like auto generated scripts to make the differences to go away and it doesn't compare any data.
It's just a small, free utility that shows you schema differences :)
Make a table and store your version number in there. Just make sure you update it as necessary.
CREATE TABLE version (
version VARCHAR(255) NOT NULL
)
INSERT INTO version VALUES ('v1.0');
You can then check the version number stored in the database matches the application code during your app's setup or wherever is convenient.
SQL Compare by Red Gate.
Which RDBMS is this, and how complex are the potential changes?
Maybe this is just a matter of comparing row counts and index counts for each table -- if you have trigger and stored procedure versions to worry about also then you need something more industrial
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