I need to make my code for where the data is inserted into 'Class_1' there are actually 3 score columns (Score_1, Score_2, Score_3) as the application I am building requires the database to keep a record of the last three entered scores. The problem with the code is that every time the data is added it will create a new entry and so what I need the program to do is check to see if the First_Name and Last_Name are present in another entry and if so, update that entry, then what I would like to do is check to see if score_1 has a value present and of course if this is true, skip score_1 and input the data into score_2 but I am completely new to C# so any help here would be much appreciated!, Thankyou!
if(inpClassNumber.Text == "Class 1")
{
con = new SqlConnection(#"Data Source = (LocalDB)\MSSQLLocalDB; AttachDbFilename = C:\Program Files (x86)\Flux Infusion\Projects\Primary School Quiz System\Primary School Quiz System\Scores.mdf; Integrated Security = True");
con.Open();
cmd = new SqlCommand("INSERT INTO Class_1 (First_Name,Last_Name,Score_1) VALUES (#First_Name,#Last_Name,#Score)", con);
cmd.Parameters.AddWithValue("#First_Name", txtFirstName.Text);
cmd.Parameters.AddWithValue("#Last_Name", txtLastName.Text);
cmd.Parameters.AddWithValue("#Score", lblScore.Text);
cmd.ExecuteNonQuery();
}
If you are running SQL Server 2008 or newer you can use a MERGE TSQL:
MERGE Class_1 AS target
USING (SELECT #First_Name, #Last_Name, #Score) AS source (fName, lName, score)
ON (target.First_Name = source.fName and target.Last_Name = source.lName)
WHEN MATCHED THEN
UPDATE SET
Score_1 = #Score,
Score_2 = Score_1,
Score_3 = Score_2
WHEN NOT MATCHED THEN
INSERT (First_Name, Last_Name, Score_1)
VALUES (#First_Name, #Last_Name, #Score);
.
The above code keeps the most recent score in column Score_1, the second most recent in Score_2, and so on.
Here is the link to the TSQL documentation.
Related
I am trying to add train objects to a database to hold their details for persistence.
I have it working so I can add the trains to a list. But when I try to set up an INSERT statement to add the train objects details to a database. nothing is added to my database when i check it after. I don't get any errors thrown anywhere either.
Can anyone see anything wrong with my INSERT statement?
//If the type combobox has Express selected
if (cbxType.Text == "Express")
{
//Create a new train with its specific details
Train train = trainFactory.TFactory("Express");
//Checks for error when making train
if (train == null)
MessageBox.Show("Can't Create Train");
else //Executes adding a new Express Train
{
//Stores the details of the textboxes/Combo boxes into the train details for each Train object
train.Type = cbxType.Text;
train.Departure = cbxDepartStation.Text;
train.Destination = cbxDepartStation.Text;
//Converts the time into DateTime format before passing to variable
train.DepartureTime = TimeSpan.Parse(txtDepartureTime.Text);
//Converts the date into DateTime format before passing to variable
train.DepartureDay = DateTime.Parse(txtDepartureDay.Text);
//If intermediate stops are selected. Throw exception
if (chbPeterborough.IsChecked == true || chbDarlington.IsChecked == true ||
chbYork.IsChecked == true || chbNewcastle.IsChecked == true)
{
throw new Exception();
}
//If first class radio button is checked, sets first class to true, else false
if (chbFirstClass.IsChecked == true)
{
train.FirstClass = true;
}
else
{
train.FirstClass = false;
}
//Adds a train object to the train list with its specific details
trains.add(train);
//String to hold all the Intermediate stops together in one for displaying to user
string intStops = string.Join(", ", train.IntermediateStop.Where(s => !string.IsNullOrEmpty(s)));
//Sql sequence to connect to database and insert details of each train
SqlConnection con = new SqlConnection(#"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=|DataDirectory|\Trains.mdf;Integrated Security=True");
SqlCommand cmd = new SqlCommand();
cmd.CommandType = System.Data.CommandType.Text;
cmd.CommandText = "INSERT train (id, departure, destination, type, intermediate, departure_time, departure_date, sleeperBerth, firstClass) " +
"VALUES ( #trainID , #departure, #destination, #type, #intermediate, #dep_time, #dep_date, #sleep, #first)";
cmd.Parameters.AddWithValue("#trainID", train.TrainID);
cmd.Parameters.AddWithValue("#departure", train.Departure);
cmd.Parameters.AddWithValue("#destination", train.Destination);
cmd.Parameters.AddWithValue("#type", train.Type);
cmd.Parameters.AddWithValue("#intermediate", intStops);
cmd.Parameters.AddWithValue("#dep_time", train.DepartureTime);
cmd.Parameters.AddWithValue("#dep_date", train.DepartureDay);
cmd.Parameters.AddWithValue("#sleep", train.SleeperBerth);
cmd.Parameters.AddWithValue("#first", train.FirstClass);
cmd.Connection = con;
con.Open();
cmd.ExecuteNonQuery();
con.Close();
The whole AttachDbFileName= approach is flawed - at best! When running your app in Visual Studio, it will be copying around the .mdf file (from your App_Data directory to the output directory - typically .\bin\debug - where you app runs) and most likely, your INSERT works just fine - but you're just looking at the wrong .mdf file in the end!
If you want to stick with this approach, then try putting a breakpoint on the myConnection.Close() call - and then inspect the .mdf file with SQL Server Management Studio - I'm almost certain your data is there.
The real solution in my opinion would be to
install SQL Server Express (and you've already done that anyway)
install SQL Server Management Studio
create your database in SSMS, give it a logical name (e.g. Trains)
connect to it using its logical database name (given when you create it on the server) - and don't mess around with physical database files and user instances. In that case, your connection string would be something like:
Data Source=.\\SQLEXPRESS;Database=Trains;Integrated Security=True
and everything else is exactly the same as before...
Also see Aaron Bertrand's excellent blog post Bad habits to kick: using AttachDbFileName for more background info.
Try to change this code
cmd.CommandText = "INSERT train (id, departure, destination, type, intermediate, departure_time, departure_date, sleeperBerth, firstClass) " +
"VALUES ( #trainID , #departure, #destination, #type, #intermediate, #dep_time, #dep_date, #sleep, #first)";
into
cmd.CommandText = "INSERT INTO train (id, departure, destination, type, intermediate, departure_time, departure_date, sleeperBerth, firstClass) " +
"VALUES ( #trainID , #departure, #destination, #type, #intermediate, #dep_time, #dep_date, #sleep, #first)";
I only added INTO in your INSERT text query
I have a task where i want to copy all data from one database to another database & skipping 2 tables. There are more than 200 tables.
I have table structure ready for my 2nd databas.
So as a solution i created a page & on a button click i have below code :-
DataSet ds = new DataSet();
string connectionString = "Data Source=COMP112\\MSSQLSERVER2014;Initial Catalog=HCMBL;Integrated Security=True;Persist Security Info=True";
SqlConnection con = new SqlConnection(connectionString);
//render table name from database
string sqlTable = "SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE='BASE TABLE' and TABLE_Schema='" + Session["SchemaName"].ToString() + "' and TABLE_NAME!='ENTRY' and TABLE_NAME!='OT' and TABLE_NAME!='BL_ENTRY' and TABLE_NAME!='BL_OT'";
con.Open();
SqlDataAdapter da = new SqlDataAdapter();
SqlCommand cmd = new SqlCommand(sqlTable, con);
cmd.CommandType = CommandType.Text;
da.SelectCommand = cmd;
da.Fill(ds);
con.Close();
//render connection string from WebConfig file
string strcon = ConfigurationManager.ConnectionStrings["SPSchema"].ConnectionString;
for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
{
if (!(ds.Tables[0].Rows[i]["TABLE_NAME"].ToString().Contains("Asp")))
{
string deleteQuery = "Truncate table " + Session["SchemaName"].ToString() + "." + ds.Tables[0].Rows[i]["TABLE_NAME"];
con.Open();
SqlCommand cmdDelete = new SqlCommand(deleteQuery, con);
cmdDelete.ExecuteNonQuery();
con.Close();
DataSet dataSet = new DataSet();
SqlConnection conn = new SqlConnection(strcon);
conn.Open();
string selectData = "select * from " + Session["SchemaName"].ToString() + "." + ds.Tables[0].Rows[i]["TABLE_NAME"];
SqlCommand command = new SqlCommand(selectData, conn);
DataTable dataTable = new DataTable();
SqlDataAdapter dataAdapter = new SqlDataAdapter(selectData, conn);
dataAdapter.FillSchema(dataSet, SchemaType.Mapped);
dataAdapter.Fill(dataSet);
dataTable = dataSet.Tables[0];
conn.Close();
if (dataSet.Tables[0].Rows.Count > 0)
{
//Connect to second Database and Insert row/rows.
SqlConnection conn2 = new SqlConnection(connectionString);
conn2.Open();
SqlBulkCopy bulkCopy = new SqlBulkCopy(conn2);
bulkCopy.DestinationTableName = Session["SchemaName"].ToString() + "." + ds.Tables[0].Rows[i]["TABLE_NAME"].ToString();
bulkCopy.WriteToServer(dataTable);
conn2.Close();
}
}
}
As i run the above code after inserting data in less than 10 tables, it gives out of memory exception & program crashes.
How to handle this? I tried increasing the memory capacity of SQL Server but still same error.
Is there any other way to achieve the task?
What you are doing is very far from the best solution. You are using an ASP.NET MVC process to get all data of your entire database into memory, and then outputting it to another database. If your database is anything more than small and trivial, that will most definitely fill your process's alotted memory.
This type of task should never be done through the memory of a process, but rather using some form of Backup/Restore pattern.
You should look into SSIS projects and create an extract, transfer, and load (ETL) solution, which can be triggered from your ASP.NET MVC solution asynchronously.
An SSIS solution can be triggered from C# code in this way:
var app = new Application();
var package = app.LoadPackage("compiled-package.dtsx", null);
var results = package.Execute();
See this question for a little more information (not specifically about duplicating databases, but has information about triggering SSIS packages from code): How to execute an SSIS package from .NET?
Alternatively
You also have the option of running a query against both databases at once, however this requires some additional plumbing to be done. The user account of your ASP.NET MVC solution needs to have access to both databases. If your databases are hosted on different servers, you also need to link one server to the other: Create linked servers
To perform an insert directly from the output of a select, consider this:
string source = "NAME_OF_SOURCE_DATABASE";
string target = "NAME_OF_TARGET_DATABASE";
string schema = Session["SchemaName"].ToString();
string table = ds.Tables[0].Rows[i]["TABLE_NAME"];
// Uncomment this if you need to deal with autoincrement columns
/*string idInsQuery = $"SET IDENTITY_INSERT {target}.{schema}.{table} ON";
var idInsCommand = new SqlCommand(idInsQuery, conn);
idInsCommand.ExecuteNonQuery();*/
string insQuery = $"INSERT INTO {target}.{schema}.{table} SELECT * FROM {source}.{schema}.{table}";
var insCommand = new SqlCommand(insQuery, conn);
insCommand.ExecuteNonQuery();
// Uncomment this if you need to deal with autoincrement columns
/*string idInsQuery2 = $"SET IDENTITY_INSERT {target}.{schema}.{table} OFF";
var idInsCommand2 = new SqlCommand(idInsQuery2, conn);
idInsCommand2.ExecuteNonQuery();*/
This will only work if the table structures are identical. There might be problems with autoincrement ids or columns with default values, too.
This will copy data from a table in database 1 to a table in database 2
Insert into db2.dbo.table2 (col1,col2)
Select col1,col2 from db1.dbo.table1
Run this sql statement and the data will be copied without a round trip to your app.
Let me know if you find my approach is useful.
First of all, why you want to write down one whole application to do this job while SQL Server have inherited property to do it.
My approach would be configure an Linked Server and configure it which tables you want to copy and which one not.
https://learn.microsoft.com/en-us/sql/relational-databases/linked-servers/create-linked-servers-sql-server-database-engine
Secondly, You can just write down simple stored procedure and schedule that in your sql server to push into another server database as per your schedule. In this way you can control it in N number of ways. I mean about controlling any dependencies(Table level or Business level).
To do this in t-sql, you can use the following system stored procedures to schedule a daily job. This example schedules daily at 1:00 AM. See Microsoft help for details on syntax of the individual stored procedures and valid range of parameters.
DECLARE #job_name NVARCHAR(128), #description NVARCHAR(512), #owner_login_name NVARCHAR(128), #database_name NVARCHAR(128);
SET #job_name = N'Some Title';
SET #description = N'Periodically do something';
SET #owner_login_name = N'login';
SET #database_name = N'Database_Name';
-- Delete job if it already exists:
IF EXISTS(SELECT job_id FROM msdb.dbo.sysjobs WHERE (name = #job_name))
BEGIN
EXEC msdb.dbo.sp_delete_job
#job_name = #job_name;
END
-- Create the job:
EXEC msdb.dbo.sp_add_job
#job_name=#job_name,
#enabled=1,
#notify_level_eventlog=0,
#notify_level_email=2,
#notify_level_netsend=2,
#notify_level_page=2,
#delete_level=0,
#description=#description,
#category_name=N'[Uncategorized (Local)]',
#owner_login_name=#owner_login_name;
-- Add server:
EXEC msdb.dbo.sp_add_jobserver #job_name=#job_name;
-- Add step to execute SQL:
EXEC msdb.dbo.sp_add_jobstep
#job_name=#job_name,
#step_name=N'Execute SQL',
#step_id=1,
#cmdexec_success_code=0,
#on_success_action=1,
#on_fail_action=2,
#retry_attempts=0,
#retry_interval=0,
#os_run_priority=0,
#subsystem=N'TSQL',
#command=N'EXEC my_stored_procedure; -- OR ANY SQL STATEMENT',
#database_name=#database_name,
#flags=0;
-- Update job to set start step:
EXEC msdb.dbo.sp_update_job
#job_name=#job_name,
#enabled=1,
#start_step_id=1,
#notify_level_eventlog=0,
#notify_level_email=2,
#notify_level_netsend=2,
#notify_level_page=2,
#delete_level=0,
#description=#description,
#category_name=N'[Uncategorized (Local)]',
#owner_login_name=#owner_login_name,
#notify_email_operator_name=N'',
#notify_netsend_operator_name=N'',
#notify_page_operator_name=N'';
-- Schedule job:
EXEC msdb.dbo.sp_add_jobschedule
#job_name=#job_name,
#name=N'Daily',
#enabled=1,
#freq_type=4,
#freq_interval=1,
#freq_subday_type=1,
#freq_subday_interval=0,
#freq_relative_interval=0,
#freq_recurrence_factor=1,
#active_start_date=20170101, --YYYYMMDD
#active_end_date=99991231, --YYYYMMDD (this represents no end date)
#active_start_time=010000, --HHMMSS
#active_end_time=235959; --HHMMSS
Let me know in case you need more details on this.
Thanks,
Ayan
I have an .accdb file with four tables in it
Product_Particulars
Cust_Details
Variable_fields
Permanant_fields
The number of column in the 'Variable_fields' table is not fixed (changed using 'ALTER TABLE' OleDb nonQuery). But it has two fixed columns 'Tranx_ID', 'Tranx_time'.
I want to accomplish something that will enable me to add data in the 'Tranx_ID' Column in a new row from a textBox without caring about other columns in the table (i.e. other cells in that row, in which the 'textBox.Text' is attempted to insert) and save the row with data in only one cell.
N.B.: I am actually using OleDb & I will use the 'Tranx_ID' for Updating that particular row using an OleDbCommand like,
"UPDATE Variable_fields " +
"SET [This column]='" +thistxtBx.Text +
"',[That column]='" +thattxtBx.Text +
"'WHERE ([Tranx_ID]='" +textBox.Text+ "')";
The exception is caused by the fact that one or more of the columns that you don't insert cannot have NULL as value. If you can remove this flag and allow a null value then your INSERT could work or not for other reasons.
Indeed you use a string concatenation to build your query and this is a well known source of bugs or a vector for an hacking tecnique called Sql Injection (I really suggest you to document yourself about this nasty problem)
So your code could be the following
string query = #"UPDATE Variable_fields
SET [This column]= #this,
[That column]=#that
WHERE ([Tranx_ID]=#trans";
using(OleDbConnection con = new OleDbConnection(....constringhere....))
using(OleDbCommand cmd = new OleDbCommand(query, con))
{
con.Open();
cmd.Parameters.Add("#this", OleDbType.VarWChar).Value = thisTextBox.Text;
cmd.Parameters.Add("#that", OleDbType.VarWChar).Value = thatTextBox.Text;
cmd.Parameters.Add("#trans", OleDbType.VarWChar).Value = transTextBox.Text;
int rowsInserted = cmd.ExecuteNonQuery();
if(rowsInserted > 0)
MessageBox.Show("Record added");
else
MessageBox.Show("Record NOT added");
}
Helpful links:
Sql Injection explained
Give me parameterized query or give me death
Using statement
I am relatively new to the world of databases and C# and I am having a problem getting my data tables to update according to changes I make via a C# program. I am using a TableAdapter to issue commands to the database.
In my program I have a form that allows a new row to be added to the data table. As far as I can tell this works, because the rest of my program can access the new information by querying the database.
this.patientInfoTableTableAdapter.InsertNewPatient(
this.FirstName, this.LastName, this.StreetAddress, this.City, this.State, this.Zip,
this.Email, this.Phone, this.DOB, this.Gender);
I can even stop the run of the program and restart it, and the added data is still accessible. However, when I view the data table directly, the added row is not there and the next time I run the program the table has reverted to the unmodified state in the program's eyes as well.
I do have an Update method that I use every time I go through this process, but it has no effect, either on retaining the added row or any changes to the existing rows:
this.Validate();
this.patientInfoTableBindingSource.EndEdit();
this.tableAdapterManager.UpdateAll(this.eMRSDatabaseDataSet);
MessageBox.Show("Update Successful");
I always see the MessageBox appear and I do not get any errors.
I have come to the conclusion that some setting or property for my database is amiss, and I could use some help figuring out my problem.
In case it helps, the database queries for the involved code follow:
INSERT INTO [PatientInfoTable] ([First_Name], [Last_Name], [Street_Address], [City], [State], [Zip], [Email], [Phone], [DOB], [Gender]) VALUES (#fName, #lName, #sAddress, #city, #state, #zip, #email, #phone, #dob, #gender)
and
UPDATE PatientInfoTable
SET Street_Address = #saddress, City = #city, State = #state, Zip = #zip, Email = #email, Phone = #phone, Gender = #gender
WHERE (Patient_ID = #p11)
These queries were generated using the Visual Studio query builder.
I would greatly appreciate any suggestions!
query = "Update mcm_class Set class_status='" +
dgv.Rows[i].Cells[1].ToString() + "' where class_id ='" +
dgv.Rows[i].Cells[0].ToString() + "'"+ "AND"+" med_id='" +
lst_med.SelectedValue.ToString() + "'";
cmd = new SqlCommand(query, con);
con.Open();
cmd.ExecuteNonQuery();
con.Close();
I am building a web application in asp.net using C#. I have the Form where the user should register and then can login. I am having a problem in making the web app know that the name which the user picks is either "already exists" or not. If it already exists it should not insert the same name and display a message saying "user name already exists". I have tried the SqlDataReader but no luck.
protected void Register_Button_Click(object sender, EventArgs e)
{
SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["BJ_Player_String"].ToString());
SqlCommand cmd = new SqlCommand();
SqlCommand cmd2 = new SqlCommand();
SqlDataReader data_reader;
String name = TextBox2.Text;
String date = TextBox3.Text;
try
{
conn.Open();
cmd = new SqlCommand("Insert into BJ_Player (Player_Name, D_O_B) Values (#Player_name, #D_O_B)", conn);
cmd = new SqlCommand("Select Player_Name from BJ_Player WHERE Player_Name = #Player_name", conn);
cmd.Parameters.Add("#Player_name", SqlDbType.NVarChar).Value = name;
cmd.Parameters.Add("#D_O_B", SqlDbType.Date).Value = date;
cmd.Connection = conn;
data_reader = cmd.ExecuteReader();
cmd.ExecuteNonQuery();
if (data_reader.HasRows)
{
lblPlayerNameExists.Visible = true;
}
else
{
// do nothing
}
}
Make Player_Name unique in database then it will give you exception when you try to insert. You have to use unique constraint.
You have to give command type also and check you assigned both queries to same cmd object
in your code you're inserting data in your DB and then you are examining that the name is the same or not.
first you should search the name in your DB and then if there isn't any record with that name ,you should add your record.
I usually do it in one of two ways:
Create stored procedure that will check for name uniqueness and insert new record if everything is ok. It should return status as numeric code that you will check.
Check for name uniqueness before saving it using as a part of validation process.
Using the merge statement may help with this. Merge performs insert, update, or delete operations on a target table based on the results of a join with a source table.
Basically it inserts when needed, and updates when needed. Often times referred to as an upsert. but it gets the job done.
Here is a link to a site explaining how to use merge. Looks like a good article.
http://www.kodyaz.com/articles/sql-server-2008-t-sql-merge-statement-example.aspx
If you would like to write a model function to do that then
Leave it for ajax check which is pretty similar to the second
method
Issue "Select username from DB-table" to retrieve
usernames then check the username input against them before
displaying a view to report a problem if any or showing a message to
tell the user that "this name is valid", for example.