I have a fairly complex database that has worked for quite a while. Today I went to troubleshoot something and I got a non-sensical error.
In my macro, first I create detail tables. Then I number each row sequentially in the detail table with a VBA script. Then I create a summarized version of that table including the just the key info like SKU and row number. (The rest of the details are added back later using the row number). The numbering script is working. The detail tables have the row numbers. However the summary table does not have the row numbers after running the macro. If I manually click the queries to add the summary tables, the numbers magically appear.
Please help. This database has worked for over a year without this problem.
Honestly it sounds like its corrupt. MS Access uses the Jet Engine which is known for bloating dB size and quite easily becoming corrupt.
You can see by the odd behaviour, the program is having trouble with the underlying file. If you open a new Access DB it won't exhibit the same problems.
The best bet is to recreate the dB from scratch or port it to SQL Server, PostGres, MySQL, SqlLite etc and put the application logic in a program - even if its a VB6 app, though I'd recommend .Net.
I've got the code to strip out every thing and recreate the MS Access dB here:
https://stackoverflow.com/a/16158027/495455
Related
I have a VB.NET program that I wrote 20 years ago and last updated 7 years ago. I have gotten a new computer and new version of Visual Studio recently.
The program uses a DB created with MS Access via the OLEDB mechanism. I originally created the DB connection by dragging and dropping tables from the DB into a VB window. This generates a lot of code automagically that I have never had to look at in the past. This code takes care of the DB queries and updates. Code I have explicitly written adds, modifies or deletes rows from the tables.
In the past I have been able to manually add a column to the Access DB and get the automatically generated code to update and make that column available to my code.
I am trying to do that now and I've either forgotten a crucial step or the newest version of Visual Studio is not compatible with my ancient code. The symptom is the new column does not get updated when I update all the other columns. If I look at the automagically generated code (in routine InitilizeComponent) it has lines like:
Me.OleDbUpdateCommand5.CommandText = resources.GetString("OleDbUpdateCommand5.CommandText")
Me.OleDbUpdateCommand5.Connection = Me.dcWageLossDB
Me.OleDbUpdateCommand5.Parameters.AddRange(New System.Data.OleDb.OleDbParameter() {New System.Data.OleDb.OleDbParameter("CaseId", System...
where in the arguments of the last call it lists all the columns EXCEPT for my my new one.
Note that while the new column does not get properly added to the DB queries, it does get added to internal structures so that in my code I can refer to the new column by name and set its value.
I know this question is rather fuzzy. It is not practical to provide the (quite long and complex) code. Since the problem probably depends on the long history, it also is not practical to try to create a small simple version of it.
I'm just hoping someone has run into this problem and knows the solution.
Thanks
I have already tried graphically deleting and adding back all the tables in the .xsd file used in the query via the solution explorer - data connections. It didn't help.
In desperation, I also tried modifying my hand the automagically generated code, adding it the new column in a fashion similar to what it had for all the old columns. I couldn't make that work.
Okay so I am working in Web Forms but the problem would also apply to MVC I am assuming since both have the option of creating a users database on project creation. I deleted a data table on accident and updated the database instead of deleting the database itself because I was trying to recreate it with the seed data. I didn't realize that deleting a data table would do something different from deleting the database itself. The only backup I have is pretty old, so I would prefer to use a different way to fix things if that exists. How would I fix things?
I have it working now. What I did to fix it was I went to my back up although it could have just been a brand new project, both would have been fine, and I copied the SQL script for the data table that I deleted. Then I went to my broken program and created a new data table in the spot where it was before and replaced the code with the code from the back up. I saved it and hit update and it updated the database for me.
I have just started an internship in I've had to learn a lot on my own. I'm learning MS SQL Server, but having a strange problem. I have a DB that has four small tables. Each one has a script to drop the table, recreate the table (I've avoided FK dependencies for the time being), and execute a demo query.
Problem 1: When I first started SQL Server Managmenent Studio would execute the script, but one table didn't show up in the Object Explorer. If I tried to execute a demo query from the same .sql file, it executed with no problem. If I tried to access it from another .sql, the table didn't exist. After many times of successfully executing the script, it finally just showed up.
Problem 2: Similar problem. When I updated one table, the changes wouldn't be reflected in queries.
Problem 3: Queries will fail, but if I click execute again with no changes being made, it will usually work correctly.
Problem 4: When I use an alias for a field name, sometimes the alias is recognized and sometimes it isn't. I've literally had single query in which the alias would work in one place, but not work in another and I had to use a fully qualified name.
I've tried the refresh and refresh local cache, but those seem to have no effect. If I exit Management Studio, that seems to usually fix the first two problems.
Am I going nuts or am I just in the dark about some weird specifics of SQL Server?
First of all, when you make a schema change you need to right-click on the "Tables" node for the database in management studio and hit refresh.
If you change a column or something in a table, right-click the table and refresh.
The refresh local cache only updates the intellisense stuff, and the refresh only updates the GUI. If you modify a table with SQL and do not refresh it in the UI, the query can still use the updated table.
If you query fails, you either have a bad query or it's not pointed at the database or connection you think it is.
For aliases, there are places where they will not work (update statements, for example) but if you don't post queries where they don't work we cannot read your mind and tell you what's wrong.
If you have specific queries that are failing, post them.
I'm a programmer (mostly C++) who has moved into a non-software workplace. However, I don't have much experience with database stuff at all.
TL;DR: If we compare Crystal Reports to just writing scripts that execute SQL queries and parse the results, is there anything that CR can do that isn't possible via SQL queries & scripts? I'm talking purely in terms of extracting data - not making pretty documents.
Detail:
At my workplace they have a process where you run a bunch of Crystal Reports, modify the date range to the current month, manually export each to excel, delete the rows and columns that aren't needed, and then cut and paste into a summary excel document that is used by management.
To me, this is pretty crazy and stupid. I'd like to automate/script most of it.
So I have two options:
Learn Crystal Reports and try to modify the existing reports to be more automated.
Dump CR and just learn SQL and do the whole thing programmatically with scripts working with CSV files or something.
I'd much rather learn SQL since it's more general and useful. But I need to be assured that I can get the data output that I need (without writing a million lines of code to reproduce CR myself.)
So yeah, I'm looking for an answer like, "The two are equivalent. Anything you can do in CR you can do easily via scripts and SQL," or "If you need to group records into categories based on a parameter and then sum their one of their fields, then CR will do it much more easily than raw code," to push me in one direction or another.
Edit:
Some additional detail. At the moment my crystal reports run a database query, and then crystal does things like, "don't display the records that are returned, instead group the records by Field A and then display the count of how many records in each group."
Is functionality like this difficult to reproduce via SQL coding? I wouldnt want to have to write a python (or whatever) script to parse and manipulate the data from plaintext CSV, for example.
You can't just compare SQL and CR - they have different purpose. SQL (in this context) is data source, CR is pretty output formatter. For excel you would need data, not formatted output. Excel combined with SQL can give you all CR options (dynamic crosstab reports, charts etc) what you can't get directly from SQL data.
BTW, creating SQL views or procedures is often needed to overcome CR limitations; from this standpoint SQL has lot of more options than CR.
I personally would go with SQL+Excel route. In our company we're using simply SQL+CR without postprocessing, sometimes SQL+Excel. Our customers are using different approaches.
But like said by other people, choice of tools depends on more things. Who has to redesign reports? Who will maintain these reports? How often requirements change? Are there more uses for CR reports besides sourcing Excel tables? Who will be waked up at night, if reports do not work?
Management perpective:
In many I will say mostly cases management does not know SQL. So if a manager for E.g.HR wants to know staus about something then how he will get that status?? This is where Crystal reports come into picture, Using crystal reports they do not have to worry about SQL; they will just enter required fields and get their data.
Programmer perspective:
Simple data outputs can be achieved through SQL but consider a scenario where you need to pull details as well as summary. I agree it can be done via SQL but consider the overhead of time and proficiency required to develop such output using sql. I bet it wont be that easy to develop such output using sql as compared to crystal. So I will say learn both SQL and crystal, you will get to choose the tool to apply for your requirement.
You can write SQL and drop it into the Crystal Report. Best of both worlds, and possibly faster performance than the drag-and-drop Crystal functionality.
You will see some response time lag when the report runs.
There are actually a few things that Crystal Reports can do that are very tricky using plain SQL Queries as Crystal Reports can access the entire dataset in a single formula and can do things at runtime.
However unless you have some really crazy complex Crystal Reports I would recommend building a tool in Excel that can one click the info straight into a new sheet.
I did this and it got me a promotion, not kidding :P
I have a custom Excel Addin I can give you code to that basically does this:
On open, connects to the database and downloads a list of menu options connected to views and procedures
Adds these menu options into a new Ribbon tab within Excel
When one is clicked, runs the view and dumps the entire dataset (properly formatted) into a new sheet
Advantage of this is you can update the main menu list and each view it references without making any changes to the file or re-issuing anything to everyone.
Crystal could be helpful if you want to create a document with a specific layout , logos etc. and show some data on it. Export to excel from Crystal repot is not easy - usually there are a lot of empty columns and rows and each report should be tweaked to avoid that.
If you need to export some data from a SQLServer database to excel your best option will be SSIS ( I guess you have a license for SQL Server). If you don't have license for SSIS or you are using for example Access database there are also some inexpensive tools, which can retrieve data from any database ( not just SQLServer) and export it to excel. I would suggest you to check this one: http://www.r-tag.com. It can run Crystal reports and SQL reports so you can start using your crystal reports immediately and start transforming them to SQL reports whenever you have time for that. Both reports could be exported to excel.
i fixed this by editing excel sql, Left(Column_maxLength, 250)
this resolved my issue
in my case if even if i read left 250 character is enough
Presently am working with an Excel spreadsheet that makes at least 10 database queries to external Microsoft Access *.mdb files. For each project my company works on, we have a specific excel file related to that project, so we have hundreds of these files. Usually when an analyst opens the Data tab and click on "Refresh All" the refresh completes in a minute or two; however, on a new project for a given excel file it is taking at least an hour to complete the refresh. Here is an example of one of the connection strings:
DSN=MS Access Database;DBQ=W:\Projects\Analysis\project.mdb;DefaultDir=W:\Projects\Analysis\Analysis;DriverId=25;FIL=MS Access;MaxBufferSize=2048;PageTimeout=5;
And here is the associated query:
SELECT Field.FieldNumber, Field.FieldName, Field.GroupMnemonic, Field.ClientFieldID
FROM Field Field
ORDER BY Field.FieldName
I have spent time studying various websites discussing slow excel issues like http://msdn.microsoft.com/en-us/library/ff700515.aspx; however, these websites deal more with calculations and VBA whereas I suspect the performance problem is somewhere in an access file. Does anyone have any suggestions on how to troubleshoot and resolve this issue? TIA.
UPDATE: As suggested in the answer below by JohnFx, I checked the queries and found that they had no definite keys, so and so added keys in the Microsoft Access database generation like this:
CREATE UNIQUE INDEX PIndex ON [myTable] ([KEY])
Run the queries individually directly in Access to rule Excel in or out as part of the problem. If the queries are still slow in Access consider adding indexes on any columns that are in being sorted or filtered on.