This ultimately depends on your structure / objects that you are using, but if you are simply storing a string for each of the rows, you should be able to determine if a row is empty or not by using the
String.IsNullOrEmpty() method :
//If your row is null or empty - this will be true (indicating it is empty)
if(String.IsNullOrEmpty(YourRow.Text))
{
//Handle logic for an empty row
}
Do you have any examples of the code that you are currently using? It maybe helpful for providing a more detailed answer.
Can you provide more info on your database schema? Also, will the third table have a row for the user regardless whether they completed the third survey?
The first table contain a list of all users for my website. It also contain three columns, one for each survey (a total of three survey). Each are set to NULL by default. This help me identify whether or not the user had completed a survey. We can tall that
the Record Table.
The next three tables are empty and will be populated with data when a user completed a survey and click the submit button. We can call that Survey Table 1, Survey Table 2, and Survey Table 3.
What happens is, when a user complete the first survey and click submit, a couple things happens: the Record Table get updated. It identify the user by it ID, then update the first column for the first survey by changing from NULL to 1. Then Survey Table
1 get a new row containing the data from the first survey that is cross-referenced with the same user's ID.
So when I create a Result Page that display each user's data from the survey - I will be able to display the data from the first survey by using Survey Table 1, seachable by the user's ID. However, Survey Table 2, and Survey Table 3 will still be empty.
I am looking for a way to detect exactly that -- Over time, numerous of users will complete the survey.
Suppose Survey Table 1 have 5 rows, each with unique user data from the first survey. However, Survey Table 2 will have only 4 rows. As one user completed the first survey but not the second survey.
What I want to do is -- I search Survey Table 2 and detected that there's no row for that user that exist. Thus an empty row -- in another word, no record found.
I hope this make sense? Please let me know and I'll try to be more clear! I was constantly in and out of the office all day yesterday. Hopefully, I'll be more attentive today! Thank you!!
Let me provide you a good idea. Your idea is a good one, you need to check that user went through these steps, if value is 1 he complete the survey if not then he has not!
Lets make it short.
Suppose you are having ONE table only named as Survey, there are 15 columns, each column being followed by a column names "survery_1", "survery_2". If the value for them is 1 you then get the value from there, if the value for this is 0 then you can show
that the survey has not been taken, and the value should be saved in front of these columns like
You can use a LEFT JOIN to detect if there are no matching records across a relationship:
SELECT SurveyTable1.ID, SurveyTable2.ID, SurveyTable3.ID
FROM RecordTable
LEFT JOIN SurveyTable1 ON RecordTable.UserID = SurveyTable1.UserId
LEFT JOIN SurveyTable2 ON RecordTable.UserID = SurveyTable2.UserId
LEFT JOIN SurveyTable3 ON RecordTable.UserID = SurveyTable3.UserID;
Yep. There is theoretically no limit to the number of tables you can include in a query except what the system's resources allow (Sql Server 2008 onwards - previous to that the limit was 256 tables in 2005).
Yep. There is theoretically no limit to the number of tables you can include in a query except what the system's resources allow (Sql Server 2008 onwards - previous to that the limit was 256 tables in 2005).
256 Tables in one Query! O.o
However, thanks alot! I will try using this in my app too.
Read more of my web development posts on my website. Thank you.
Member
45 Points
124 Posts
Detecting empty row in table
Aug 20, 2013 12:38 PM|TmoodASP|LINK
Is there a way to detect an empty row in a table?
For example, I have three survey form - thus three tables for each survey.
A user completed two survey. So two tables are populated but not the third.
How do I detect if the third table (and that row for that specific user) is empty?
Contributor
4010 Points
1926 Posts
Re: Detecting empty row in table
Aug 20, 2013 01:22 PM|Afzaal.Ahmad.Zeeshan|LINK
In your code you can do something like:
foreach (var row in result) { if(row.RowName == "") { // instead of "" you can use null, or " "; to check white space // write something.. } }All-Star
114593 Points
18503 Posts
MVP
Re: Detecting empty row in table
Aug 20, 2013 01:31 PM|Rion Williams|LINK
This ultimately depends on your structure / objects that you are using, but if you are simply storing a string for each of the rows, you should be able to determine if a row is empty or not by using the String.IsNullOrEmpty() method :
//If your row is null or empty - this will be true (indicating it is empty) if(String.IsNullOrEmpty(YourRow.Text)) { //Handle logic for an empty row }Do you have any examples of the code that you are currently using? It maybe helpful for providing a more detailed answer.
All-Star
194004 Points
28027 Posts
Moderator
Re: Detecting empty row in table
Aug 20, 2013 01:46 PM|Mikesdotnetting|LINK
Can you provide more info on your database schema? Also, will the third table have a row for the user regardless whether they completed the third survey?
Member
45 Points
124 Posts
Re: Detecting empty row in table
Aug 21, 2013 08:40 AM|TmoodASP|LINK
What I did for my survey:
I have four tables:
The first table contain a list of all users for my website. It also contain three columns, one for each survey (a total of three survey). Each are set to NULL by default. This help me identify whether or not the user had completed a survey. We can tall that the Record Table.
The next three tables are empty and will be populated with data when a user completed a survey and click the submit button. We can call that Survey Table 1, Survey Table 2, and Survey Table 3.
What happens is, when a user complete the first survey and click submit, a couple things happens: the Record Table get updated. It identify the user by it ID, then update the first column for the first survey by changing from NULL to 1. Then Survey Table 1 get a new row containing the data from the first survey that is cross-referenced with the same user's ID.
So when I create a Result Page that display each user's data from the survey - I will be able to display the data from the first survey by using Survey Table 1, seachable by the user's ID. However, Survey Table 2, and Survey Table 3 will still be empty. I am looking for a way to detect exactly that -- Over time, numerous of users will complete the survey.
Suppose Survey Table 1 have 5 rows, each with unique user data from the first survey. However, Survey Table 2 will have only 4 rows. As one user completed the first survey but not the second survey.
What I want to do is -- I search Survey Table 2 and detected that there's no row for that user that exist. Thus an empty row -- in another word, no record found.
I hope this make sense? Please let me know and I'll try to be more clear! I was constantly in and out of the office all day yesterday. Hopefully, I'll be more attentive today! Thank you!!
Contributor
4010 Points
1926 Posts
Re: Detecting empty row in table
Aug 21, 2013 12:04 PM|Afzaal.Ahmad.Zeeshan|LINK
Let me provide you a good idea. Your idea is a good one, you need to check that user went through these steps, if value is 1 he complete the survey if not then he has not!
Lets make it short.
Suppose you are having ONE table only named as Survey, there are 15 columns, each column being followed by a column names "survery_1", "survery_2". If the value for them is 1 you then get the value from there, if the value for this is 0 then you can show that the survey has not been taken, and the value should be saved in front of these columns like
survery_1 opt_1 opt_2 survery_2 opt_1 opt_2 opt_3 ...
But make sure the column names are not alike.
All-Star
194004 Points
28027 Posts
Moderator
Re: Detecting empty row in table
Aug 21, 2013 02:46 PM|Mikesdotnetting|LINK
You can use a LEFT JOIN to detect if there are no matching records across a relationship:
Contributor
4010 Points
1926 Posts
Re: Detecting empty row in table
Aug 21, 2013 03:24 PM|Afzaal.Ahmad.Zeeshan|LINK
Is it legal to use more than one join?
All-Star
194004 Points
28027 Posts
Moderator
Re: Detecting empty row in table
Aug 21, 2013 04:22 PM|Mikesdotnetting|LINK
Yep. There is theoretically no limit to the number of tables you can include in a query except what the system's resources allow (Sql Server 2008 onwards - previous to that the limit was 256 tables in 2005).
Contributor
4010 Points
1926 Posts
Re: Detecting empty row in table
Aug 22, 2013 03:49 AM|Afzaal.Ahmad.Zeeshan|LINK
256 Tables in one Query! O.o
However, thanks alot! I will try using this in my app too.