Using DataSets in vb.net - vb.net

When looping through a DataSet why do you have to user the "(0)"??? Every time I dont use it I get an error, so I have learned use it but not really sure why? Im just trying to get a better understanding of why this is used. Here is an example below:
for each row as datarow in ds.tables(0).rows
next
'******Note: If i use this I get an error ********************
for each row as datarow in ds.tables.rows
next
And also another question comes to mind, with regards to this question is that locally through visual studio 2010 i use that for each statement and it works as expected, but if I use that for each on a production server, if there are no records i get an error, so what I have to do is do a record count, then if ok then go ahead with the for each. Is there anyway around that?

Because your ds.tables is an array of tables, and 0 is the first index of the tables array. It doesn't work in the second scenerio because you aren't defining an index, which is required to access a specific element within your array.

The issue with question one is that the dataset can hold many tables, so you need to either supply an index or table name to access the rows in that table. I am not sure why there is a difference between locally and production, it should act the same.
Wade

Related

PowerApps filter returning incomplete data record...?

I have an Azure SQL database, and my records inside table Spiderfood_RITMData in that database includes 13 different fields. Lots of stuff. I have confirmed in SQL-SMS that the records have data in each field.
There are way more items in the database than PowerApps can see using LOOKUP (1600-9000 records or more). However, I know FOR A FACT that there is only ONE record that has any given value in the NUMBER column. It's not a primary key, but it is unique in the table.
In PowerApps, I am trying to pull that field so that I can eventually parse out the individual items.
So, the commands I'm trying are:
ClearCollect(MLE_test1, Filter('Spiderfood_RITMData', "RITM2170467" in Number));
ClearCollect(MLE_test2, Search('Spiderfood_RITMData',"RITM2170467", "Number"));
However, the Collection results for MLE_test1 and MLE_test2 both are empty EXCEPT for the value of NUMBER. Say what?!
I'm trying to use the examples posted on https://learn.microsoft.com/en-us/powerapps/maker/canvas-apps/functions/function-filter-lookup but I am honestly getting baffled by this.
How should I be formatting this call such that I can pull the whole record?
Big picture explanation: I need to do a lot of data LOOKUPS into my table Spiderfood_RITMData table, but it has way more than 2000 rows, and PowerApps will not perform the Lookup correctly. So my presumably smart idea is to create a MUCH SMALLER "version" of Spiderfood_RITMData as a local collection, using a more delegateable function (such as FILTER or IN). If I filter by all records containing the values of NUMBER, then I go from, say a 10,000-record SQL table to a 10-record Collection. And I can do LOOKUPS against that collection for the rest of the function (uh, I think -- I'm still trying to experiment accordingly). Please let me know if this is crazy or not.
LookUp is just used to get one record, instead try this:
ClearCollect(MLE_test1, Filter('Spiderfood_RITMData', "RITM2170467" = Number));
This gets a collection with all the items where Number is = to "RITM2170467"
Collections are limited to only 2000 records in each collections.
I had same issue. Go to App settings. Under Upcoming Features make sure Explicit column selection is turned off. Hope this does it for you.

Retrieve results from a batch of SQL queries in Pentaho or Postgres?

I'm still relatively new to SQL and Pentaho.
I've pulled a table with two different IDs and need to run a query for each specific instance.
For example,
SELECT *
FROM Table
WHERE RecordA = 'value in column A'
AND RecordB = 'value in column B'
I need the results back, either appended to new columns in the original table or part of their own text file output.
I was initially looking at using a formula for this inside of Pentaho, but couldn't quite figure it out. Since I have the query written I threw it into Excel and got the concatenated results (so a string of 350 or so queries that I need to run). I'm just not sure how to accomplish this - I tried the Execute SQL Script inside of Pentaho but it doesn't seem to do output?
Any direction would be useful. I've searched a little but have come up short so far, possibly because I am still pretty new to this platform.
You can accomplish this behavior in a lot of ways, with a "Database Lookup" step for example, but I usually do that in a quite easy way and here is a example for your tests, I hope it helps.
The idea here is to have two Table input steps, the first one will fetch the IDs we want to look at. For example you may use a SQL query similar to note on the left. The result will be a 1 column stream of rows.
Next we have a Table Input that reads the rows received and executes it's query for each row. I'll add a screenshot with the options that I selected.
What it does is replace a placeholder '?' with the data that is received. If you need two columns use two '?' but remember that it will replace the first one with the first column and the second one with the second column
And you are good to go. Test it a couple of times and good luck.
And the config for the second table input.

delphi create sql select statement at runtime

I am attempting to create a sql statement in XE8 at runtime to search an oracle database based on the value in a textbox. I find multiple different ways that attempt to explain this online, but I am not understanding what it is asking.
I want to search a server based on a select statement and populate TDB components (labels only) based on the data. The furthest I have gotten is to get data populated, but the where
' ... somevalue = ' + textbox.text;
seems to have no effect.
What components do I need to make this happen? I am connected to the database, and it appears that I can get some kinda data out of it, but I can't seem to figure out how to filter the results. Obviously, I cannot create this sql statement at design time as the value of textbox.text will change depending on the user's input.
My error was in how to dynamically change what the data aware components got data as it would not always be the same. I had to manually go in and modify their datafield properties. Once I did this, my query functioned correctly.

Recreating Hyperion Reports in Access and SSRS (Microsoft Visual Studio 2012) using the Prior and Next Functions

I have several reports in Hyperion that I use the next and prior functions to look at the row right before and/or the row after.
To do this, I sort the data in a certain way to make sure the prior or next functions in hyperion find the right rows above or below the current row. For example, I may sort 2 other rows to get the right sorting for the functions to work correctly.
Now I would like to be able to find a way to recreate these reports in Access and SSRS.
I have been looking for a way to accomplish this in either or both. But at the moment I have not found a way.
If I need a unique field to help with this, I can concatenate between about 4 fields to make a column that has a unique key for each row.
Could anyone point me at a good article or know how to do this? I would really appreciate it very much, thank you!
Using sorting and grouping, probably similar to what you did in Hyperion, you can mostly accomplish this in SSRS using expressions:
FIRST() will return the first row of your current scope of data
LAST() will return the last row of your current scope of data
PREVIOUS() will return the previous row of your current scope of data, or NULL if there are no more previous rows.
Of course, what's missing is something like NEXT(). For whatever reason, Microsoft didn't see fit to include a NEXT() option. Instead, you need to grow your own solution. I see a few common strategies used for this:
A LOOKUP (or LOOKUPSET/MULTILOOKUP) function against your report dataset, combined with FIRST or ROWNUMBER to get
Write some custom code to do the sorting/indexing for you, see here for one idea: http://sqlreportsq.blogspot.com/2012/03/can-we-get-next-row-value.html
Do whatever data maniuplation in you need to do via your SQL using LAG/LEAD

How to get info from a listbox populated by an SQL query?

The title says the vague question, but, I will be more specific. I'm more of a hardware oriented person with some experience in VB, Java, and C++. I've been asked to modify a form in Access which uses SQL queries to take information from a database. The edit I am trying to make is to a form that has selections to narrow down the data it queries from to appear in a listbox in the center of the form (so, like radio buttons to specify a certain height or weight of an object in the database). The selections, as they are selected, concatenate additional specifications to an string that is then run as an SQL query. What I am trying to accomplish is to take a column of the narrowed-down data and find the maximum number in the column and the average of the numbers in the column. It seems really simple and know how to do that with regular lists and arrays, but I'm at a loss with my limited knowledge. I've considered making another SQL string, but in another part of the form, it was done with two strings (so, one to put the data in the listbox from the database and one to pull the specific column of the narrowed down data). That being said, it doesn't seem logical to me to pull the same sets of data each time, so I'm wondering if I can just pull the info from the already pulled info. At the bottom of the code set is this:
ItemList.RowSource = vSQLStock
ItemList = Null
ItemList.Requery
QuoteList.RowSource = vSQLNonStock
QuoteList = Null
QuoteList.Requery
Both vSQLStock and vSQLNonStock have their own sets of SQL strings that are run by this function, or as far as I can tell (I'm still studying up on SQL) put the narrowed down items in the QuoteList listbox. What I'm asking is if there is a way with any function that can be used to go through this information? Specifically, take a column and do some calculations on the data. I don't want to run another SQL query and bog down the server, but rather manipulate the data on the user's computer.
An example of what happens is the user selects whether the item is stock/nonstock, searches by the name/code/ID, and then puts all the matches on the listbox on the form. The listbox shows lines of data with columns like Name, Cost, Size, Weight, etc. of which I am looking to do calculations on the Cost column. Hopefully this is enough information; I appreciate any advice.
It looks from your question like you are attempting to get the Maximum and the Average from a SQL query.
the syntax:
SELECT MAX(myColumn) as MyMax, AVG(myColumn) as MyAverage
FROM myTable
WHERE . . .
Will return the Maximum and Average Values within SQL Server or within MS Access
If you're really bound and determined to do this locally with the data you've already retrieved from the server, then you probably need to look into working with adodb.recordsets. You can kind of treat it like an array. Kind of.
I really recommend querying the server for the data you need though. It's a world simpler.
dim rs as ADODB.Recordset
Set rs = QuoteList.Recordset
rs.MoveFirst
Do Until rs.EOF
' loop through recordset doing something
rs.MoveNext
Loop