All Questions
10,059
questions
195
votes
28
answers
285k
views
Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints
I make an outer join and executed successfully in the informix database but I get the following exception in my code:
DataTable dt = TeachingLoadDAL.GetCoursesWithEvalState(i, bat);
Failed to ...
- 11.3k
134
votes
14
answers
245k
views
Data is Null. This method or property cannot be called on Null values
I'm working on an application where one can get information on movies from a database as well as add, update and delete the movies. In the database I have three tables (Movie, Genre and MovieGenre <...
- 20.4k
132
votes
7
answers
308k
views
Index (zero based) must be greater than or equal to zero
Hey I keep getting an error:
Index (zero based) must be greater than or equal to zero and less than the size of the argument list.
My code:
OdbcCommand cmd = new OdbcCommand("SELECT FirstName, ...
- 6,050
120
votes
6
answers
503k
views
How to read SQL Table data into a C# DataTable
I've read a lot of posts about inserting a DataTable into a SQL table, but how can I pull a SQL table into a C#/.NET DataTable?
- 1,337
114
votes
8
answers
151k
views
How to get Database Name from Connection String using SqlConnectionStringBuilder
I do not want to split connection strings using string manipulation functions to get Server, Database, Username, and Password.
I read the following link and read the accepted answer, I found that is ...
- 7,419
88
votes
15
answers
96k
views
EF 4.1 exception "The provider did not return a ProviderManifestToken string"
I am trying to replicate an example found on MSDN. I am using ASP.NET and EF 4.1 (CTP?). I've used NuGet to install the EntityFramework package.
I am getting this error: The provider did not return a ...
- 3,938
88
votes
9
answers
31k
views
Are Parameters really enough to prevent Sql injections?
I've been preaching both to my colleagues and here on SO about the goodness of using parameters in SQL queries, especially in .NET applications. I've even gone so far as to promise them as giving ...
- 36k
82
votes
9
answers
478k
views
Connecting to SQL Server using windows authentication
When I was trying to connect to SQL Server using the following code:
SqlConnection con = new SqlConnection("Server=localhost,Authentication=Windows Authentication, Database=employeedetails");
con....
- 919
81
votes
6
answers
141k
views
Howto? Parameters and LIKE statement SQL
I am writing a searching function, and have thought up of this query using parameters to prevent, or at least limit, SQL injection attacks. However, when I run it through my program it does not ...
- 12.3k
73
votes
5
answers
37k
views
Is there a good LINQ way to do a cartesian product?
I have a class structure like so:
Person
Dogs (dog 1, dog 2, etc)
Puppies (puppy A, puppy B, etc)
There is one person. He has 1..n dogs. Each dog has 1..n puppies.
I want a list of all the possible ...
- 40.2k
64
votes
7
answers
124k
views
Default port for SQL Server
I need to know the default port settings for the following services
SQL Server
SQL Browser
SQL Reporting services
SQL Analysis services
I need to know the port settings for these services for ...
- 15.2k
61
votes
12
answers
48k
views
The 'System.Web.Security.SqlMembershipProvider' requires a database schema compatible with schema version '1'
I have a SQL Server 2008 DB with many tables filled with data and I used SQL Server Management Studio to generate a SQL dump by using the Script Wizard : Tasks -> Generate Scripts -> Script All ...
- 14k
56
votes
2
answers
56k
views
Entering keys manually with Entity Framework
I'm trying to use Entity Framework code first for a simple database project and I run into a problem I simply cannot figure out.
I noticed EF was setting the ID for my tables automatically ...
- 597
54
votes
5
answers
39k
views
Pass table valued parameter using ADO.NET
How to pass table valued parameter to stored procedure using ADO.NET?
- 563
53
votes
3
answers
23k
views
EntityFramework Same Table Many to Many Relationship
I have a table called Products which obviously contains products.
However, I need to create related products. So what I've done is create a junction table called product_related which has two PKs. ...
- 2,775
46
votes
4
answers
95k
views
In memory database in .net [closed]
I have a .net application where i want to use In-Memory data structure. Please advice me how it works in compare to the physical database.
- 1,281
45
votes
1
answer
2k
views
ASP.NET Site Maps
Does anyone have experience creating SQL-based ASP.NET site-map providers?
I have the default XML file web.sitemap working properly with my Menu and SiteMapPath controls, but I'll need a way for the ...
- 56.6k
44
votes
4
answers
182k
views
How to use the ConfigurationManager.AppSettings
I've never used the "appSettings" before. How do you configure this in C# to use with a SqlConnection, this is what I use for the "ConnectionStrings"
SqlConnection con = new SqlConnection();
con....
- 2,187
44
votes
4
answers
56k
views
Two foreign keys referencing the same primary key
Is this okay to have two foreign keys in one table referencing one primary key of other table?
EmployeeID is a primary key in the employee table and appearing as a foreign key twice in the timesheet ...
- 3,059
43
votes
3
answers
311k
views
How to convert DataSet to DataTable
I am retrieving data from a SQL table so I can display the result on the page as a HTML table. Later I need to be able to save that table as a CSV file.
So far I have figured out how to retrieve the ...
- 993
42
votes
7
answers
64k
views
Connect to AS400 using .NET
I am trying to build a .NET web application using SQL to query AS400 database. This is my first time encountering the AS400.
What do I have to install on my machine (or the AS400 server) in order to ...
- 1,780
41
votes
8
answers
100k
views
How to get the client IP address from SQL Server 2008 itself?
I have a trigger for insert/update/delete. That is working fine. Also, I need the client's IP address from where the changes are made. That I need in T-SQL, that means, not in any web form but in the ...
user240141
41
votes
10
answers
16k
views
Images in database vs file system
We have a project coming up where we will be building a whole backend CMS system that will power our entire extranet and intranet with one package. The question I have been trying to find an answer to ...
- 411
36
votes
4
answers
132k
views
Nullable DateTime conversion [duplicate]
Possible Duplicate:
c# why cant a nullable int be assigned null as a value
Im trying to convert my reader[3] object which is datetime to be null if there is no lastPostDate for a Forum but it ...
- 5,781
35
votes
11
answers
223k
views
Return value using String result=Command.ExecuteScalar() error occurs when result returns null
I want to fetch 1st row 1st cell value from database it works well with below code . But when there is no result found it throws Exception.
How to handle with DBNull .
Should i change my query ? ...
- 10.2k
34
votes
4
answers
141k
views
How to use executeReader() method to retrieve the value of just one cell
I need to execute the following command and pass the result to a label. I don't know how can i do it using Reader. Someone can give me a hand?
String sql = "SELECT * FROM learer WHERE learer.id = " + ...
- 12.4k
33
votes
3
answers
39k
views
Timeout expired with SqlBulkCopy
I'm using SqlBulkCopy to restore tables from xml backups. One of the table backup is ~200MB large and has a lot of records.
I'm having error:
Timeout expired.
The timeout period elapsed prior to ...
- 13k
31
votes
6
answers
381k
views
Select query to get data from SQL Server
I am trying to run the SQL Select query in my C# code. But I always get the -1 output on
int result = command.ExecuteNonQuery();
However, the same table if I use for delete or insert works...
...
- 559
31
votes
7
answers
31k
views
sql runs fast in ssms slow in asp.net
I have been having this problem for a couple of weeks now. The problem is that the query takes 4-5 minutes to run on the website and at most 2 or 3 seconds to run in ssms. Also I found that after I ...
- 393
31
votes
4
answers
33k
views
Which is the "best" data access framework/approach for C# and .NET?
(EDIT: I made it a community wiki as it is more suited to a collaborative format.)
There are a plethora of ways to access SQL Server and other databases from .NET. All have their pros and cons and it ...
30
votes
10
answers
54k
views
Fastest way to retrieve data from database
I am working on a ASP.NET project with C# and Sql Server 2008.
I have three tables:
Each user has a specific value for each data field, and this value is stored in the DataFieldsValues.
Now I ...
- 3,961
29
votes
10
answers
141k
views
System.Data.SqlClient.SqlException: Invalid column name 'phone_types_phone_type_id'
I'm trying to get information from some of my models that have a foreign key relationships to my main employee model. If I map out each model individually, I can access them like normal with no ...
- 3,628
29
votes
4
answers
109k
views
Occasionally Getting SqlException: Timeout expired
I have application running on my server. The problem with this application is that daily I am getting nearly 10-20, System.Data.SqlClient.SqlException Timeout expired. The timeout period elapsed prior ...
28
votes
8
answers
137k
views
The wait operation timed out. ASP
I created an internal website for our company. It run smoothly for several months and then I made a major update due to user suggestion. When I run in live, it run normally. Then suddenly one of my ...
- 477
27
votes
4
answers
46k
views
The ObjectContext instance has been disposed and can no longer be used for operations that require a connection. in Reference table
I have two tables Customers and Country and use ( Entity Framework with vs 2012 )
And the model class
using System;
using System.Collections.Generic;
public partial class Customer
{
...
- 3,919
26
votes
4
answers
42k
views
What does "Data Massage" mean?
I am doing some reading, and came across avoiding an internalStore if my application does not need to massage the data before being sent to SQL. What is a data massage?
- 21.8k
26
votes
4
answers
31k
views
What's the difference: Windows Authentication, Passport Authentication and Form Authentication?
Just going to start making a web application and was wondering which was better, or at least what are the main differences between them (as it probably matters what I am using them for)?
Windows ...
user450549
26
votes
9
answers
7k
views
User permission error when accessing "user instance" database from ASP.NET
The server hosting csharpindepth.com has recently been migrated.
Most of it is working fine, but I can't get at the database used to hold errata, notes etc.
Relevant details:
32 bit Windows Server ...
- 1.5m
24
votes
14
answers
8k
views
What is the Reason large sites don't use MySQL with ASP.NET?
I have read this article from High Scalability about Stack Overflow and other large websites. Many large high traffic .NET sites such as plentyoffish.com, MySpace and Stack Overflow all use .NET ...
- 64.3k
24
votes
4
answers
32k
views
Distributed transaction completed. Either enlist this session in a new transaction or the NULL transaction
Just curious if anyone else has got this particular error and know how to solve it?
The scenario is as follow...
We have an ASP.NET web application using Enterprise Library running on Windows Server ...
- 6,552
23
votes
2
answers
92k
views
C# Invalid attempt to call Read when reader is closed
I am having Invalid attempt to call Read when reader is closed error when I am doing 3 tier project in C# language.
What I am trying to do is retrieve address data column by joining two tables ...
user2531590
22
votes
6
answers
160k
views
How to save SELECT sql query results in an array in C# Asp.net
How can I save the results of an SQL query into an array?
I want to use the values (located in col1 and col2) in an IF statement, leading to my thinking of saving them in an array.
var con = new ...
- 4,028
21
votes
16
answers
41k
views
How can I avoid SQL injection attacks in my ASP.NET application?
I need to avoid being vulnerable to SQL injection in my ASP.NET application. How might I accomplish this?
- 15.2k
21
votes
4
answers
167k
views
Selecting multiple columns with linq query and lambda expression
I'm new to C# ASP.NET, and am working on my first application.
I'm trying to create a linq statment that return an arrary.
I have a table of products. I want to be able to select name, id, and price,...
- 4,843
21
votes
8
answers
134k
views
Using the Web.Config to set up my SQL database connection string?
Can anyone help me out please? I'm confused.
I want to set up my connection string so I can just call it from my Web.Config file.
I need a way to call it from my code, please make a little example. ...
- 40.7k
20
votes
10
answers
63k
views
HTML Encoding in T-SQL?
Is there any function to encode HTML strings in T-SQL? I have a legacy database which contains dodgey characters such as '<', '>' etc. I can write a function to replace the characters but is there ...
- 2,138
20
votes
2
answers
21k
views
.mdf" failed with the operating system error 2(The system cannot find the file specified.)
protected void register_Click(object sender, EventArgs e)
{
AddUser(userName.Text, password.Text, confirm.Text);
}
void AddUser(string name, string pass, string confirm)
{
...
- 594
20
votes
3
answers
36k
views
How to enable MultipleActiveResultSets
I have the following connection string in my code:
SqlConnection conn = new SqlConnection(WebConfigurationManager.ConnectionStrings["RaiseFantasyLeagueConnectionString"].ConnectionString);
My ...
- 527
19
votes
5
answers
26k
views
ExecuteScalar(); With scope_identity() Generating "System.InvalidCastException: Specified cast is not valid" [duplicate]
I've have a form which accept various data (through textboxes and a checkboxlist) and on the click event they insert all the data into a table and selects the scope_identity then store it in a ...
- 3,460
19
votes
2
answers
35k
views
Get byte[] from the SqlDataReader?
I have a table with a varbinary(MAX) parameter. After executing the query, I will store the result in SqlDataReader as it has multiple columns as output.
SqlCommand cmd = new SqlCommand("select ...
- 2,187