i have the following piece of VB.NET code:
Dim conn As New MySql.Data.MySqlClient.MySqlConnection(ConnectionString)
conn.Open()
Dim sql = "SELECT * FROM users"
Dim com = New MySql.Data.MySqlClient.MySqlCommand(sql, conn)
Dim ds As New DataSet("dsUsers")
[Code]...
My question is : If I have two or more fields in table1 pointing to the ID field of Table2...would I be able to set the datarelation between the two tables by setting the 1st relation between table1 to table2 against the relevant ID fields from both the tables and then go on to create and add new datarelation between the same tables again...but this time against the 2nd field from the table1 to the ID field of table2. Or would I need to load table2 that many number of times into the dataset as there are fields pointing to it from the table1?
View 7 RepliesI have a datagridview (parent) and a (well, several) listboxes that I am trying to create a relation with.Datagrid has master records which contain ID fields to lookup tables. The lookup tables are populated into listboxes.I have 1 dataset which contains tables for my datagridview(s) and my listboxes.I need to create the relations so that when they click on a row in the grid, it shows the corrisponding item in the listboxes as well.Problem is, a lot of the ID's in the parent table are empty... so when I try to create the relation, it blows up.
Code: "This constraint cannot be enabled as not all values have corresponding parent values." I'm doing like like so
Code:
lo_relation = New DataRelation("RelationName",DataGridTableIDColumn, ListboxTableIDColumn)
I tried to reverse it, naming the ListboxTableColumn as the parent. That allows the relation to build, but I can't set the Listboxes .ValueMember to that...I'm kind of stumped... as it needs to be a two way relationship.
1) When the parent record (datagridview) changes, it changes the value in the listbox
2) When the Listbox changes, it changes the "value" in the parent datatable so it can be updated.
Would I resolve my issue if I populated the parent with a "default" ID in each field (say 0)... if the database value is null? And furthermore, populate each lookup table with a "blank" default value as well? i.e. First record is ID = 0, Desc = ''?
I have two combobox, cmbCountry and cmbLocationI have dataset with 3 table, first table for Country value, second table with Location value and then I have table Apartments with IDCountry and IDLocation.I have 2 datarelation, ApartmentCountry, ApartmentLocationThen I bind the last table with cmbCountry and cmbLocation
View 2 RepliesI've written a bunch of queries that bring back a set of results that look like the following. I have a user level column in an employees table which I'm trying to pull the value from. Only one result (number) will ever be returned. For instance the query will be like: Select username, userlevel from employees where username = "joe" So i'd be bringing back just the level, say 7.
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i need to update the table based on the two user.
for eg:
update table1 set rating=@rate where User1=@userid / user2=@userid
so i need to write a single query which satisfy the condition for both the users user1 and user2.if i pass the @userid ,if it matches the user's id it should update user1 record. if the id whcih i pass is user2's id then it should update the user2 rec.How to check for this condition in a single query...
I want to update two tables by single query
View 2 Replieslinq querying various nested tables in a dataset? I can't find something like that on the net.
View 1 RepliesI have a string like "Hello'World" and a Data Table with some records in it. One of those records is "Hello'World".he problem is, when I do a .Select in the Data Table, it only tries to search for the "Hello" part and throws an error on "World" because it interprets the ' (single. cuote) like the closing cuote on sql.DataTable.select("text = 'Hello'World'")I have gone through msdn doc, and it says I can escape some characters with [] brackets or f.slashes , but I just can't figure out: .select("text = 'Hello[']world'")
View 1 RepliesFor a school programming project we are supposed to create a database with 2 tables country, and continent.then we populate country with every country name, population and continentID. For continent we populate with each continent name.
i have completed this step, and i am able to run a linq query to display all countries and corresponding continent into a datagridview. My problem arises because we are supposed to display each record one at a time, and be able to cycle through one at a time. I cannot for the life of me figure out how to do this.
for example if i made a query to select all countries in africa, i want to beable to display the name of the country, and population in textboxes. then have a next button that will go to the next record.
I am trying to do a SQL query that checks for the presence or absence of a character's occurance in a field / column as a condition to retrieve the row. In this case I only need to test for existance of the specified character and in a similar query to test for the non existence. Not where it is or how many, just is it there or is it notI am using VB express.net 2008 and it uses, I think, MS SQL Server 2008.Using VB's instr() I can tell straight away if a string does or doesn't contain a character, but I would like to know this before I retrieve the row.
using the
WHERE .... and [mytable.myfield] LIKE 'Q'
or
WHERE .... and [mytable.myfield] NOT LIKE 'Q'
produces a result, but not a correct result. It does something but I can not say that it is working even part way.CHARINDEX gets an undefined function error MATCHES also gets an undefined function error?CONTAINS looks like it should work but I am still getting sytax errors with it, so I don't know how to use that predicate yet.
I am using vb.net and sqlite as database. I am using below scenario to insert multiple records in database using a single query.
INSERT INTO TableName (FirstCol, SecondCol)
SELECT 'First' ,1
UNION ALL
SELECT 'Second' ,2
UNION ALL
SELECT 'Third' ,3
[Code] .....
For less records it is working very well.But when I am inserting about 800 records at a time, executenonquery is throwing the following exception:
SQLite error
Too many terms in compound SELECT.
I am using datarepeater on my windows form to populate records from a temp table. I want to write query to insert records for an employee in a single row rather than multiple rows. For example: I am displaying records of one month only. so i know the definite number of columns. Normally if we use select * from Temp ' it will display and i can populate in a datagrid.
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I want to know if it is possible to perform a mySQL query to get a single record (searched for by ID) and then split each field into a seperate text box.I think im ok with the SQLQuery to get the record. its the splitting it into individual text boxes that im strugling with.
View 1 RepliesI have a LINQ query that groups and counts on a single dgv cell. What I want to do is group and count on 2 dgv cells. So I modified my existing query by adding a SELECT statement highlighted :
CODE:
But I am getting an error on the second select variable stating: Range variable 'Value' is already declared
What I have read shows that I can select more than one variable.
What I am trying to achieve is this:
Original
CODE:
Result:
CODE:
Ok, the basic situation: Due to a few mixed up starts, a project ends up with not one, but three separate databases, each containing a portion of the overall project data. All three databases are the same, it's just that, say 10% of the project was run into the first, then a new DB was made due to a code update and 15% of the project was run into the new one, then another code change required another new database for the rest of the project. Again, the pertinent tables are all exactly the same across all three databases.
Now, assume I wanted to take all three of those databases - bearing in mind that they can't just be compiled into a single databases due to Primary Key issues and so on - and run a single query that would look through all three of them, select a given set of data from each, then compile those three sets into one single result and return it to the reporting page I'm working on.
we are using Punch Machine for Attendance with zkemkeeper.dll and geting AttLog using Vs.net 2010.How can Get Records from SQL Query? my table structure like this
LogID int P.K.
DeviceIP varchar
EnrollNo int
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I am writing a message system on my server, the xml is something like this
<xml>
<entry>
<sender>[code]....
my problem now i guess is 2 fold, i wish to combine the first 3 queries into a single query and place in a list or a collection or is there a way to do this with a single query that will give me my desired result?
Dim obj_DataTable As New System.Data.DataTable("Category")
Dim obj_DataSet As New DataSet()
'Declaring the array of DataColum to hold the Primary Key Columns
[code].....
Say I have a code with 3 methods that do some pretty intensive work. Would executing these methods on 3 seperate threads be faster then executing them one after the other on a single core cpu? And what if it's a dual core or HT?
View 8 RepliesI want to know how to Update / delete the table records in ASPNETDB.MDF in single update / delete query ?
View 1 RepliesI am trying to make a list, separated by a comma, of entries from a single column in a SQL database. I have been spending the last several days searching for a way to do this, but every thing I found either didn't work, or wasn't exactly what I was looking for.
The query will pull all the email address that are not null. What I need to know is how to take the result of that query and make it look like this:
email0@address.com, email1@address.com, email2@address.com, etc, etc, ...
I feel like I should know this, but for the life of me, I can't remember nor can I find it in any of the textbooks I have.
I am using Visual Basic 2010 and SQL Server 2005. I also have access to Visual Basic 2005 if needed.
I use SqlParameters when executing database statements. I know that I can replace a single quote with two single quotes... but in the past SqlParameters took care of this for me. I have two projects.. in one, the SqlParameter does this and it handles single quotes fine, in another, it does not and I'm at a loss why (I even copied and pasted the code):
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I am trying to use the DGV to view various properties from a variety of different class instances. Is it possible to bind each cell individually?
View 9 RepliesI am trying to update a row or a single cell in ms access through vb.net. But when i update the text box named NRIC, say for example i want to update "s4522147B" to "tr4521856C" and mean while leaving the other fields the same.
But the thing is when i make the changes in nric.text (textbox), the dataset actually updates the whole column in the table instead of the selected textbox.
Below is my code for the update part
[Code].....
Here is the code:
Function getData(ByVal id As String)
Dim reader As SqlClient.SqlDataReader
Dim statement As String
[code].....
When Creating a query using the sear Criteria Builder . I keep getting the error : "The schema returned by the new query differs from the base query" what does that mean and how do i avoid this problem in future
View 2 RepliesI have a few problems i need to solve. Firstly, I am looking for a piece of code i can use to display a picture from a bank of pictures. It will work on the basis of generating a random number and loading a picture that corresponds to that number.
i.e. Dim RandNumber As Integer
Dim RandClass As New Random
RandNumber = RandClass.next(1, 10)
If RandNumber = 1 Then
Picturebox1.image = picture1
[Code]...
Secondly, can I then use subsequent picture boxes to display pictures from the same bank of images, without displaying the same image? Finally, I then need to be able to click the picture or a button beneath the picture to select it as an answer to a question and then the whole process starts again.
I am connecting to an Access database and using a parameter query with the LIKE operator to return all rows that match query. The string to search for is taken from a Textbox
sql =
"Select * FROM Allview WHERE Info Like" &
"*" &
CStr(TextBox1.Text) &
"*"
The query does not return any data in vb, but when run from access with same string, there is data returned.The connection to the database is done correctly, as I am able to return data with various other queries.
Partial code :
Dim
con As
New OleDb.OleDbConnection[code]....
I am trying to run a query an Access db from VB. The general query which I want to run is
SELECT * FROM Patient WHERE Patient.PatientID = ?
or SELECT * FROM Patient WHERE Patient.PatientLname = ?
I tried using an input box which captured the user input and pass that variable to the query, but that failed. Then I read about writing a function and using that, however, I keep getting an error which says Function not defined, but when stepping through the code, it seems to work. Here is my function: [Code]