The aim is when updating the application and update the access database without altering the data so update by update only the new tables or new columns so i want to copy the exact table with it's structure to the old database vb.net and access database.
what I've tried is detecting the differences between the old database and the new one by getting in combobox1 the only missed table and in combobox2 the missed columns in the old database in exact table already there in both database and get it's data type .
so i want to copy the entire table and then create only missed columns
thank you
There is not a built in tool to do this.
But, worse yet, there is no "generate" change scripts in Access
(Like say with SQL server).
So, how do you approach this issue? What do some of the accounting systems or commercial programs that use ms-access as the database?
Well, you have to build a kind of "up-grade" system in your software.
This means two things:
To add a new column to a table (for example), you NEVER go open up the access database with access, but "add" or "write" the code to add that field in question.
In fact, I had an applcation deployed out in the field - many desktops.
So, I had a code module called upgrade. And each time I needed a new field or whatever, then I would write the code to add that new colum.
AS LONG as I always added things into that code module, I was ok. (never break the rule for adding new fields, tables or even increasing the length of some field? - use code).
And it became quite easy after I had some code written. I would in fact often cut + paste a previous bit of code to add a new column to a table.
However, after about 5 years, that messy code module had 800+ lines of code in it!!!
But, I ALSO realized that MOST things like adding a new column or whatever? Same code over and over.
So, what I did next was built a "upgrade" table. It looked like this:
Version action SQL RunCode
2.5 AddTable tblCustomers
2.5 AddField "sql here to add table"
etc. etc.
So, I had a version number, and then I compare against the up-grade table. I had "action", and the code would simple loop this table, and do whatever.
So, for example, to add a field, you can use access "DDL" command (data definition commands - most SQL systems support this, and so does Access).
so, say like this:
' any new table code goes here:
If lngVer < 1148 Then
' add event Invoice text option
ExecuteSQLNR "ALTER TABLE dbo.Events ADD InvoiceText ntext NULL"
ExecuteSQLNR "ALTER TABLE dbo.Events ADD HideEventDate bit NULL default 0"
Or, say to increase a column lengh from 50 to 55
db.Execute "ALTER TABLE tblGroupRemind ALTER COLUMN Anotes text(255)", dbFailOnError
As noted, since oh so many the commands were VERY similar, then I started putting that information into a table, and then I would execute the required upgrades in a loop.
For a whole new table? Well, I thought that was too much code, so I always included a blank empty database - and for new tables, I would place them in that upgrade.accDB table - and "transfer/copy" the table from that upgrade database to the real one. That way, I could with great ease create a whole new table, and create in Access designers, and then add/copy that table to the "upgrade.accDB" database.
As noted? The above ideas an approaches work quite well.
In fact, over time, I found it LESS hassle while coding away to add the new column or whatever LESS effort then having to open up ms-acces, and then the table, and then the designer and make the changes.
However, the BIG issue with above?
Well, you have to get all users at least upgraded to your EXISTING schema, and there is no automated tools.
in fact, before I had any automated tools? I would open up note pad, and if I added some field to some table? I would simple type into note pad that new field in such and such table is required).
Then, when on customer site, I would open up their database, and then go look at the note pad document for the list of changes I was to make. (that is what I was doing before I started automating the process - and of course it not always practical to be "on site" or have the customers database.
But, ONCE I had all of the above working?
Then during development, I would open up my "upgrade" database, add the new row and action (new table, new column, (and more).
I even had a column that defined the function to run AFTER that one command. I mean, quite often when you add a new column, or change somthing in a table, often you need to copy data, or at least process some data after you make that change.
Once you get above going?
Then you simple NEVER make changes in the data tables directly, but use your "system" for this. And that works REALLY well.
For one, a customer could open up a older data file - say one from 4 or 5 years ago. The applcation version number would be detected, and then the upgrade code would run all though the versions to update that database. (and I did this automatic on startup - so they never even knew such a upgrade had occurred).
So, you just have to make sure that for each change you make, you put that code in your upgrade system, and you are done.
But, for existing systems? You have to look at what changes you made since last deploy, and write out the "ddl" commands (the alter table SQL commands).
There is no automated way of doing this.
As FYI?
One of the BEST and more valuable free tools in Visual Tools is the SQL server compare utility. It will not only automatic detect and tell you the changes between two SQL server databases, but will also upgrade for you. (very nice).
But, such a system is not available for Access. In fact, so valuable is that utility for SQL server, you might consider upgrading from Access to SQL server for this applcation. With that utility? I can work local, add fields, columns, tables and even stored procedures to that SQL database. When I am on site (or even by VPN), then I run that compare tool - it shows the changes, and ALSO has a button to update the target schema.
I don't know of a automated "schema" checker and updater for Access.
So, what I suggest for above ONLY works if you put such a system in place, and THEN as a developer always make your schema changes to your upgrade system, and never directly in the database with ms-access.
Related
I have been tasked with creating a method to copy the contents of an entire database to a central database. There are a number of source databases, all in Access. I've managed to copy the majority of the tables properly, 1:1. I'm using VBScript and ADO to copy the data. It actually works surprisingly well, considering that it's Access.
However
I have 3 tables that include subdatasheets (to those that don't know, a subdatasheet is a visual representation of a 1 to many relationship. You can see related records in another table inside the main table). When My script runs, I get an error. "No value given for one or more required parameters." When I open Access and try to run the same query that I've written in SQL, It pops up message boxes asking for parameters.
If I use the query wizard inside Access to build the select query, no parameters are required and I get no subdatasheet in the result set.
My question is this: how do I write a vanilla SQL query in my VBScript that does not require parameters and just gives me the data that I want?
I've tried copying the SQL from Access and running it through my VBScript and that doesn't seem to do the trick.
Any help is greatly appreciated!
As it turns out, you need to make sure that you've spelled all of the field names properly in your source query. If you've included additional fields that aren't actually in the source or destination table they'll need to be removed too.
I want to modify a column name to new name present in a table
but here problem i want to manually modify the column name present in Triggers or SP's.
Is there a any better way of doing it.
To rename a column am using this
sp_RENAME 'Tablename.old_Column', 'new_column' , 'COLUMN';
similarly how can i do it for triggers or SP's.? without opening each script?
Well, there are a bunch of 3rd party tools that are promising this type of "safe rename", some for free and some are not:
ApexSQL has a free tool for that, as MWillemse wrote in his answer,
RedGate have a commercial tool called SQLPrompt that also have a safe renaming feture, However it is far from being free.
Microsoft have a visual studio add-in called SQL Server Data Tools (or SSDT in the short version), as Dan Guzman wrote in his comment.
I have to say I've never tried any of these specific tools for that specific task, but I do have some experience with SSDT and some of RedGate's products and I consider them to be very good tools. I know nothing about ApexSQL.
Another option is to try and write the sql script yourself, However there are a couple of things to take into consideration before you start:
Can your table be accessed directly from outside the sql server? I mean, is it possible that some software is executing sql statement directly on that table? If so, you might break it when you rename that column, and no sql tool will help in this situation.
Are your sql scripting skills really that good? I consider myself to be fairly experienced with sql server, but I think writing a script like that is beyond my skills. Not that it's impossible for me, but it will probably take too much time and effort for something I can get for free.
Should you decide to write it yourself, there are a few articles that might help you in that task:
First, Microsoft official documentation of sys.sql_expression_dependencies.
Second, an article called Different Ways to Find SQL Server Object Dependencies that is written by a 13 years experience DBA,
and last but not least, a related question on StackExchange's Database Administrator's website.
You could, of course, go with the safe way Gordon Linoff suggested in his comment, or use synonyms like destination-data suggested in his answer, but then you will have to manually modify all of the columns dependencies manually, and from what I understand, that is what you want to avoid.
Renaming the Table column
Deleting the Table column
Alter Table Keys
Best way use Database Projects in Visual Studio.
Refer this links
link 1
link 2
you can do what #GorDon suggested.
Apart from this,you can also play with this query,
select o.name, sc.* from sys.syscomments sc inner join sys.objects o
on sc.id=o.object_id where sc.text like '%oldcolumnname%'
this will return list of all proc and trigger.Also you can modify filter to get exact list.then it will be very easy for you to modify,manually.
But whatever you decide,don't simply drop old column.
To be safe,even keep back up.
This suggestion relates to Oracle DB, however there may be equivalent solutions in other DBMS's.
A temporary solution to your issue is to create a pseudocolumn. This solution looks a little hacky because the syntax for a pseudocolumn requires an expression. The simplest expression I can think of is the case statement below. Let me know if you can make it more simple.
ALTER TABLE <<tablename>> ADD (
<<new_column_name>> AS (
CASE
WHEN 1=1 THEN <<tablename>>.<<old_column_name>>
END)
);
This strategy basically creates a new column on the fly by evaluating the case statement and copying the value of <<old_column_value>> to <<new_column_value>>. Because you are dynamically interpolating this column there is a performance penalty vs just selecting the original column.
The one gotcha is that this will only work if you are duplicating a column once. Multiple pseudocolumns cannot contain duplicate expressions in Oracle.
The other strategy you can consider is to create a view and you can name the columns whatever you want. You can even INSERT/UPDATE/DELETE (execute DML) against views, but this would give you a whole new table_name, not just a new column. You could however rename the old table, and name your view the same as your old table. This also has a performance penalty vs just accessing the underlying table.
You might want to replace that text in definition. However, you will be needing a dedicated administrator connection in sql server. Versions also vary in setting up a dedicated administrator connection. Setting up the startup parameter by adding ;-T7806 under advanced. And by adding Admin: before the servername upon logging in. By then, you may be able to modify the value of the definition.
I have used mysql for some projects and recently I moved to postgresql. In mysql when I alter a table or a field the corresponding query will be displayed in the page. But such a feature was not found in postgresql(kindly excuse me if I'm wrong). Since the query was readily available it was very helpful for me to test something in the local database(without explicitly typing the query), copy the printed query and run it in the server. Now it seems like I've to manually do all the trick. Even though I'm familiar with the query operations,at times it can be pretty time consuming process. Can anybody help me? How can I get the corresponding query to get displayed in postgresql(like in mysql) whenever a change is made to the table?
If you use SELECT * FROM ... there should not be any reason for your output to not include newly added columns, no matter how you get your results - would that be psql in command line, PgAdmin3 or any other IDE.
After you add new columns, it is possible that these changes are still in open transaction in other window or SQL command - be sure to COMMIT such transaction. Note that your changes to data or schema will not be visible to any other database clients until transaction commits.
If your IDE still does not show changes, maybe you need to refresh list of tables or if that option is not available, restart your IDE. If that does not work still, maybe you should use better IDE.
If you have used SELECT field1, field2, ... FROM ... then you must add new fields into your SELECT statement(s) - but this would be true for any other SQL implementation, MySQL included.
You could use the LISTEN / NOTIFY mechanism in PostgreSQL to notify your client on altering the database schema.
I am trying to generate some insert scripts using the SQL Server 2008 Script Wizard. Upon generating the scripts, I get the following error:
"The selected database contains foreign keys that create a cycle. Publishing data only is not supported for databases with cyclical foreign key relationships."
I've attempted to disable and remove all constraints in the database. The error is still occurring. Is there any way to get around this? Possibly make SQL ignore the constraints while generating the scripts.
On the Wizard page where you choose the radio button to select All Database Objects or Specific Objects, make sure to select All Database Objects. For some reason the tool needs something in there to generate even if you just want the table insert script.
Once I changed that radio button to All Database Objects, and selected the Advanced option to generate Type of script = Data Only, it worked all the way through.
I had the same problem as the OP. Then I tried again, this time in the advanced options, for the "types of data to script" option, I selected "schema and data" rather than data only. Then it worked for me without complaining about cyclical keys.
I was having the same issue, and I discovered today that you can use SQL Server Management Studio 2012 against a 2008 R2 DB and you won't get the error:
Sql Server Scripting Data Only: Workaround for CyclicalForeignKeyException?
Saving to file vs. to a new Query editor window seems to make it work for me on Management Studio 2008 :\
First off IMHO HLGEM's response is a bit cavalier--there are valid reasons at times to have cyclic references.
That said I think the script generator is hyper-sensitive. It seems to think just about any PK/FK pair is "cyclic" and I ended up having to use a copy of my database from which I'd stripped all keys to get the export to get beyond the "cyclical" error. A script like the following can help you drop keys globally but of course be careful!
SELECT
'ALTER TABLE ' + object_name(parent_obj) + ' DROP CONSTRAINT ' + [name]
AS Script
from sysobjects where xtype IN ('F')
[I didn't write this. See http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=46682]
Further the tool is pretty useless in terms of feedback since its report doesn't provide enough detail to narrow down where the supposed cyclical references exist.
Finally I found the tool to be pretty flaky in that I get random timeouts. One other observation that I haven't researched extensively is I think the tool may require you to start from scratch after the cyclical error to clear it's cache since I see different behavior when I use Previous button vs. starting afresh.
You can export the data by setting the script option - "Script Check Constraints" to False
Sorry this will not work :(
You will have to determine which table is causing the issue.
I was getting the same error because I didn't had a table selected in the object list (one big table I wanted to create in another script). Selecting all of the tables solved the problem.
PD: Maybe a little bit late, but searching CyclicalForeignKeyException gets first in Google.
I have an Access application that use the classical front-end/back-end approach. Yesterday, the backend got corrupted for a reason I don't know. So I opened the backend with Access 2003 and access asked me if I wanted to repair the file, I said yes and it seemed to work.
I can open the database see the tables contents and run most of the queries.
However there is an access query that doesn't work with a specific where clause.
Example :
// This works in the original DB, but not in the compacted one :
SELECT a, b, c
FROM tbl1 INNER JOIN tbl2 ON tbl1.d = tbl2.d
WHERE e = 3 AND tbl2.f = 1;
// This works in both the original and the compacted one :
SELECT a, b, c
FROM tbl1 INNER JOIN tbl2 ON tbl1.d = tbl2.d
WHERE e = 3;
When I try to run the queries, nothing happens. The access process start to use most of the CPU and the GUI stop responding. If I run the query from the query editor, I can use Ctrl+Break to stop the execution. I tried to give the query lot of time and it didn't help.
I've checked the execution plan in showplan.out and it seems correct (at least it should not takes forever to execute)
I tried to compact the DB again. I tried to import the tables in a new DB. I even tried to import the tables and their data in a mdb file that was in a now good state (from a backup).
Anyone have an idea?
Sounds like an index was corrupted and when that happens, it's dropped during the compact. Check for a system table called MSysCompactErrors -- you'll have to show hidden objects and/or system objects in Tools | Options | VIEW.
Never compact a Jet MDB without making a backup beforehand. Because of that rule, the COMPACT ON CLOSE function is completely useless, as it's not cancellable, so you always make sure it's turned off in all MDBs.
I don't know what type of meta data Access brings along when it imports a table from one database into another one. If the meta data is corrupted, importing the table to another database wouldn't necessarily resolve the problem. If practical, you might try creating the tables from scratch in a brand new database and then just exporting and importing (or copying and paste appending) the data into the new database.
I've never seen a table get corrupted like this in such a small database, although with Access anything is possible. Could there be something wrong with the data?
I'd try recreating the query fresh (new name, etc.), and see what happens.
You could even try copying it (even within the same DB or to a brand new one). If that works, the worst case scenario is you have to copy all the objects across to a new DB.
Is there an index on the field tbl2.f?
Also try going into that table in datasheet view, sort tbl2.f in ascending sequence and see if there is anything really strange in the first or last records.
Do you have access to a SQL Server installation? You could use the Upsizing Wizard under the Tools -> Database Utilities menu to copy the data to SQL Server, and see if you get the same problem there.