Best Practice - VB Projects - Using Such A Large Database With Many Tables
Feb 21, 2012
The Adventureworks database is used extensively for tutorials in Visual Basic applications. This has many tables that can be bound to a solution. What I would like to know is, when using such a large database with many tables and using lots of them, is it better to construct your program with a number of projects all under one solution or to put everything into a single project. If you use a number of projects, what is the syntax for accessing each module from a menu strip in your main form? I know how to do this in a single project - all you do is Form(x).show. In Adventureworks, you have a table for Employees that could be put into a single project with a number of forms - one for data entry, one for displaying all of the employees, a filter to a single employee, etc., etc.
If two small projects rely on each other for some reason, again the syntax for linking them could be an issue. Would it be better to combine them into a single project? My reason for asking is that I would feel safer if I created an application on a project by project basis and then brought them all together in one solution. This way they can be tested individually and then linked together where necessary. Making a disastrous mistake in one then only requires a small re-write rather than the headache caused by a total crash of the whole solution. I would like to know which option professional developers take. I am using Visual Studio 2008 Professional and SQL 2005 Express
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Apr 30, 2012
Single file for all interfaces or one file per interface definition? Balena & Dimauro's of book of 'Pratical Guidelines' advocates a single file called Interfaces.vb/cs to hold all interface definitions. Their aim is to minimise the proliferation of small files, where each holds a single interface definition.I can see benefits to both approaches. Does anyone have any strong views or experience that strongly supports one approach?
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Feb 29, 2012
I have pretty large file names that follow a standard naming practice and I am attempting to write a RegEx to match them. When you are reading the file name it follows the convention:
p_d(set of 8 numeric)_t(set of 8numeric)images.ext(any# of alphanumeric)
For example:
p_d12345678_t12345678_images.ext_0
The few I attempted brought back unrecognized escape sequence OR no matches found. For example this one brings back no matches:
fileInfo = value
'that changes depending on what file I'm looking for
RegEx("p_dd*_t" & fileInfo & "d*_images\.ext_w*")
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May 11, 2011
I'm really hoping I can describe this question in an understandable way. This is a puzzle that I have not been able to begin to solve even though I (mostly) understand it. I'm just not sure where to start, and I'm really hoping someone out there can get me headed in the right direction.
I have a LARGE table of data. It describes relationships between objects. Let's say the Y-axis has items numbered 1-1000, and the X-axis has items 1-1000 also. If item #234 on the Y-axis is related to item #791 on X, there will be a mark in the table where the row and column cross. In some industries this is referred to an a Truth Table. One can, at a glance, see how many items in a system relate to each other. The marks in the table can help to identify trends and patterns.Here's some other helpful stuff about the nature of the table:
The full range of the number of relationships (r) for each item on either axis can be 1 <= r <= axisTotal.The X and Y axis will share common items, but each axis will also have items that the other axis does not.Each item will only exist once per axis. It can be on X and Y, but it would only be on each one 1 time.The total number of items on each axis will most likely NOT be equal. Each axis could have from 50 to 1000's of items.
The end result is that this is going to be a report that needs to be printed. We have successfully printed a table that had about 100-150 items on each axis on an 11in X 17in piece of paper. Any more than that and it begins to be so small it's unreadable.
What I am trying to do is split the super large tables into smaller tables, but related points need to stay together. If I grab item 1-100 on X then I would need each item they relate to from Y.I've generated a number of these tables and, while the number of relationships CAN be arbitrary, I have never seen an item relate to all other items. So in real practice the range is more like 1 <= r <= (10% * axisTotal). If an item's relationships exceed this range, it can be split up into multiple tables, but that is not optimal at all.
At the end of the day I think we, and our clients, would be happy if a 1000x1000 item table was split into 8 to 10 printed pages of smaller, related tables.One other thing worth noting, there will be no empty rows or columns in the table. Every item on both the x and y axis will relate to at least 1 item on the opposite axis.
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Jul 25, 2012
I am using VS2008 and SQLite. I have created a database and several tables and am attempting to populate the tables with data from arrays.
The following code (example) works fine but stops after it inserts 30 to 50 records. I am running the VB code in debug mode and when it stops, I press pause to see where it is. It stops on "SQLcommand.ExecuteNonQuery()" and when I press continue (F5) it will insert another 30 to 50 records.
I do not get an error message. Is this a timeout issue? How do I keep the loop running to the end of the array?
Following is example code.
Dim
SQLconnect As New SQLite.SQLiteConnection()
Dim SQLcommand As SQLiteCommand
CODE:.....................
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Mar 15, 2009
Removing projects from VB2008 start page recent projects list. The above list is getting clogged. How do I remove items from this list?
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Feb 24, 2010
I have a database that works fine when not yet published, I connect this way: "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|Network_Info.mdb" But when I publish my project my application can't find my database and I always get an error. Any solution to this matter?
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Mar 13, 2012
I'm faced with a (fun, actually) data mining problem; I have raw ASCII files from instruments, and I want to move that data (~100 GB) into a database, then be able to run various algorithms determining correlations of time series, etc. I would like to write the mining algorithms in Visual Basic (.net, VS 2010 right now), and be able to do visualizations with VB code I have in hand.On the nature of the data: think of a set of several thousand devices, each recording a measurement at a given interval - so I'm talking time-series vectors.
I spent today re-acquainting myself with VB.NET's interface to (in one case) a Microsoft Access database. What used to be fairly simple - DAO I think it was - involved tables, recordsets, etc (and that would likely be fine). Now I seem to be required to have a weird variety of generally useless objects, e.g. 'adapters', 'datasets', etc. The problem is that I know exactly what I need, and all this extraneous stuff just gets in the way (certainly in coding complexity and opaqueness, and likely in efficiency as well).If any of these mechanisms gave me a kind of virtual access to the entire dataset, and let me control caching parameters, etc.it might be great, but I found nothing along those lines.
Anyway, I tried a number of different approaches, and none seemed at all aimed at what I need to do: efficiently do math on a large dataset. I can't believe I'm the first to have this problem, but I can find no useful wisdom out there. I'd be comfortable with pretty much any underlying database mechanism: MySQL, SQL Server, MS Access, but ideally something generally SQL based (I may eventually have to transition this entire system to draw from a client's SQL database, though that's not an overriding concern now). Other than that I want simplicity and efficiency. I thought my old ODBC techniques would work, and to some extent they do, though modifying tables seemed to have bizarre problems (no errors, but not modifications either).
I do have a fairly aggressive deadline to show some algorithm results, so my focus in the short term is to get something reasonable working *in* the short term - in other words, it's less important to me to pick the 'fastest' relational database than it is to pick a database that lets me focus on coding the algorithms, not working through tedious data access coding. If this db could be any smaller, I'd have tried to do it all 'in memory' at least for proving concepts; I don't want to have to learn an entire jargon and approach just to be able to retrieve data points, and write out new info (e.g., first derivatives of time series).
Perhaps I'll need to bite the bullet and just write something myself, a .dll perhaps just to save and restore large time series vectors. It seems a bit frightening to me that one would have to do this in this age, what with all the database systems out there, but I don't have much time to work through arcane interface logic.
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Dec 27, 2009
I am currently helping to write a Visual Basics program that was originally writing with access.The Original Access program has been used and modified over the past 5 years, During that time the database has gotten pretty big.The problem I am having is If I add the entire database to my data sources it creates data tables for every Table and Stored procedure even when they are not currently used in the program resulting in a 20+ minute build time just to debug.I am currently only adding Tables and Stored Procedures as i need them, so its not that much of a problem now, but as I continue to work and add tables the build time is going to go back up, and Id hate to have to wait 20+ minutes to test a small tweak I made.
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Oct 14, 2009
I'm trying to load a large CSV file into a Microsoft SQL Server Compact 3.5 database. I've tried using the following: Using MyReader As New Microsoft.VisualBasic.FileIO.TextFieldParser("filename.txt") MyReader.TextFieldType = FileIO.FieldType.Delimited MyReader.SetDelimiters(",")Then splitting the data with MyReader.ReadFields() etc, before using this data to add rows to a dataset in a database table in my project. However, my CSV files are very large, at above 9.5 million rows, and this takes forever, if the computer doesn't crash also. Does anyone have a better idea for what to do? I would like the CSV file to be loaded into the database table, to enable me to sort it, and undertake some querys and maths. The CSV data structure is:2,193,761.40000000000012,43,1510.22,8,1929.60000000000012,22,2564.52,22,2791.70000000000032,19,2971.6000000000004
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Aug 14, 2009
I am trying to make a database, fill it with tables and then fill the tables. I am having problems connecting to the server and am really not sure why. I have posted this thread in two areas of this site because I was not sure what was the best area to put it in. [code]
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Feb 8, 2010
[code].....
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Apr 22, 2011
I'm developing a VB.NET application to obtain data from any data source (using an odbc connection string), and because this i can't use specific .net connectors like MySql.Net connector and i can't previously know if the file/DMBS supports LIMIT parameter. This app will read data from a table in the data source and use the information to make some files. At this point there was no problem with some tables because they are less than 3,000,000 records length, but there is a table that has 5,000,000+ rows length, and when i send the query the connection is lost. I'm working with OdbcDataReader, because i read on MSDN site that this is the best way to read a table one row at time and i just use each record once.[code]...
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Jun 9, 2011
I want to write a program to do Markov chain, but my states are quite large. First of all I calculate all the transition probabilities and revenues for all states(1381860 total states), and store in a multidimensional array. Public RevArr(0 To 9, 0 To 750, 0 To 282) As Long
After that the iteration of markov chain should use these as inputs to calculate the steady-state probabilities. But when I try to run the main code I got this error.Exception of type 'System.OutOfMemoryException' was thrown.
The following is the declaration of second array I add just another dimension for storing all the iterations, but I get this error. Dim stateprob(IT + 1, 0 To 9, 0 To 750, 0 To 282) As single
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Sep 22, 2011
I have to export the data from the database to .txt file, I have the code below that does export it to .txt file but I'm having problems with this code because the data that I'm exporting is about 5 000000 records, it is quite slow and sometimes the pc can't handle it and stops the exporting.
Dim saveFile As New SaveFileDialog
If saveFile.ShowDialog = Windows.Forms.DialogResult.OK Then
command = New SqlCommand
[Code]....
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Feb 8, 2009
use the following code to create a database in ms access
Code:
'reference: Microsoft ActiveX Data Objects 2.8 Library
'reference: Microsoft ADO Ext. 2.8 for DDL and Security
[code].....
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Feb 8, 2011
I have 4k records in access database. And one of the field value contains ~100 lines each so and one other field has ~25 lines. So total database size reaches ~30MB and it takes lot of time 15-20 seconds to load the database in vb.net using odbc [URL]..and updating of any other small fields also takes time due to database being large
So as an alternative I used rtf file (txt files were not preserving all the newline characters). So these file are around 5-10kb only. But for 4k records and 2 fields I have now 8k files. And copying of these 8k rtf files is taking huge time for 5MB transfer it takes an hour or so.So is there any other alternative for storage of this data. So that it will be portable and easily loaded/accessed/updated from vb.net?
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Mar 12, 2010
how can I get all Tables from a Database, which I'm connected to. By the way, this is a MSDE Database.
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Mar 7, 2011
I've got two different tables in my database. One is Class and other one is LAREACT and both of them have a key field of MAIN FACILITY USED. In the following part of my code a DataTable will be generated based on the sum of the records on both tables.Based on the bellow code ACTIVITYLOOKUP datatable is having "MAIN FACILITY USED","Description","TypeName","Type","Id" columns. The issue happens when there is a row with the same MAIN FACILITY USED entity. The datatable will not show it (filter it?). Do you know where the problem lies? and how it will be fixed without any modification in database?
[Code]...
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Oct 7, 2010
How to bind a database having 2 or more tables in it using vb.net.
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Nov 7, 2010
I have a form with 3 datagridview controls that are bound to tables in a sql database. When the form loads for the first time the data is displayed correctly. If I add data to the db on another form then show the first form again the data displayed does not include the new data. If I close the app and then open it again then the new data is displayed.I cannot figure out how to manually refresh the gridview. I have tried calling the fill method of the adapter, using the refresh method of the gridview and parent control and form with still no luck. I have a ASP.net project I'm working on also and it is so easy to refresh the sqldatacontrol and the gridview and I would have though a win form would have been just as easy if not easier.
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Apr 9, 2010
I have a sql database and am using VB express 2008 in WPF and I want to know, how do I clear every record from a table in a dataset?
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Sep 27, 2011
I have a database (acces) with 3 tables Table one has Id nr 1000 table 2 1000000 table 3 Id nr 1000000000 First table makes Id nr from 1001 to 1999. On Id nr 1001 i have multiple ID nr on the seccond table 10010000 to 10019999 and on the second table ID nr 10010001 i have multiple ID nr on the third table. This will last a while but the tables will fill up. Now i work with the Max value to find the highest ID number and add one to it.
[Code]...
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Mar 26, 2009
how to create a local database, create some tables and set relations between those tables (just like in access) and I can show, add, edit and delete that data from a form.
but what I have yet to figure out is if I have 2 tables (i.e: tbleName, tblFood) and I want to have multiple tblFood items show for every 1 tblName item.
I've found that if I add a txtbox of the name table and a datagrid of the food table, the datagrid view shows all the food records, not just the ones for the name txtbox.
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May 28, 2009
this is my code but is not correct
Public Sub ChangePosition()
If Me.BindingContext(DataSet1, "t_bul").Position = -1 Then
Label1.Text = "Record 0 from 0 "
[Code]....
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Nov 5, 2010
My first method is trying to get all entries in one of the database tables. However when I try to build the solution this is the error I get:
<div style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;" id="_mcePaste">Error
1 Value of type 'String' cannot be converted to '1-dimensional array of String'.[code]....
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Oct 9, 2008
I am trying to connect to a SQL DB and loop through some tables. My tables are linked on the EMPLOYID field between UPR00100 and UPR00102. I want to write data as follows:
Level1, EMPLOYID, EmpName (from UPR00100) Level4, EMPLOYID, Address1, Address2,etc..
(from UPR00102)
Here is my data access code. I don't know how to code the loop. I know how to do it in SQL using a cursor but not VB 2005
Option Explicit On
Option Strict On
Imports System.Data
Imports system.Data.SqlClient
Module Module1
[Code] .....
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Jun 11, 2011
I dont know how to link my table to the database yet i already finished connecting to the application itself. i have four fields on the form as well in the database table. that is
1.word
2.lug_trans
3.Eng_trans
4.meaning
the same fields appear in the database tables. i have to fill and hen after extract the data and display it on another form in four labels
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Jun 12, 2009
hello everyone, i m using treeview control in vb .net . How do we usee a recursive function to add data at different levels from different tables in a database.
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Mar 20, 2011
I was wondering if there is any way to bind TWO different database tables to ONE textbox in VB? I've spent the whole day going through tutorials and different webpages and I've found nothing at all on this...
Well let me try to explain what I want to do exactly: basically I have multiple buttons on 'Form 1' and a textbox on 'Form 2' asking the user to insert a value which will then go to an Access database. But here is where it gets tricky for me: IF the user presses Button 1, the Value inserted on Form 2 will go to a field in the database whereas if the user presses Button 2 to open Form 2, then the value will go to somewhere else and so on.
This would be easy to do if I was to create multiple forms or multiple textboxes, 1 for each button but what I really need is 1 form/1 textbox that would work for all of them... [URL]
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