let me I have a table called to test and another table called testTwo testTwo.
I got a value (row) from the table test which is rollNo. Now Ii want to check and compare that if there is any row called rollNo rollNo exists in my testTwo testTwo table.
How can Ii do this in asp.net? Thanks.
I am adding some sample code here to get the concept that what Ii am trying to do.
what can be the way that Ii can compare my existing value with the existing table that the testTwo the tabletable has the row ( rollNO)
If your second table is DataTable, you can write something like below.
DataTable table=testTwo;//table example
DataColumnCollection columns = table.Columns;
if (columns.Contains("rollNO"))
{
....
}
Related
i have a small project in c#, in one of my forms i have a datagridview with 3 columns one of the columns is comboboxcolumn that bind with a sql server table id and name, i want to insert the datagridview values into another table in the comboboxcolumn i want to insert the id not a name, anyone can tel me how to do that please? this is my insert code
`
for (int i = 0; i < dgv_student.Rows.Count; i++)
{
sc.add_student(dgv_student.Rows[i].Cells[0].Value.ToString(),
Convert.ToInt32(dgv_student.Rows[i].Cells[1].Value),
dgv_student.Rows[i].Cells[2].Value.ToString());
}
`
the cell[1] the the combobox that display a name not the id.
In your example you have :
Name ID
X X
As your database set. When you are getting this from your database you're probably doing :
myDataGridView.DataSource = GetAllFromMyDatabase(); // Select * from stuff
myDataGridView.DataBind();
Giving you all three columns, and the value. Now, if you want to insert only one column, why not just filter the data you're getting from your database/gridview ?
myComboBox.DataSource = GetOnlyIDFromMyDatabaseOrMyDataGrid(); // Select ID from Stuff
myComboBox.DataBind();
If you're binding your asp.net control with only the data you need, rather than getting everything and then filter, you will have less overhead to think about.
I have a .csv file with around 200 columns and the order of columns changes all the time. I want to read each row from the file, identify the corresponding column names in the database, and write data to the table accordingly.
For this I can use a simple switch case checking for the name of column. Since there are 200 columns, I'm wondering if there is any other way to do it.
Example:
public void ColName(string str, Type a)
{
SampleTableName obj = new SampleTableName();
obj."str" = a;
connection.AddSampleTableName(obj);
connection.savechanges();
}
/* SampleTableName has columns: [Name, Age] */
ColName("Name","XYZ");
Output:
Name Age
XYZ NULL
Any ideas please? Thanks.
If the column names are the same you can use SqlBulkCopy and add a list of Column Mappings. The order doesn't matter, as long as the DataTable name is set.
DataTable table = CreateTable(rows);
using (var bulkCopy = new SqlBulkCopy(connectionString))
{
foreach (var col in table.Columns.OfType<DataColumn>())
{
bulkCopy.ColumnMappings.Add(
new SqlBulkCopyColumnMapping(col.ColumnName, col.ColumnName));
}
bulkCopy.BulkCopyTimeout = 600; // in seconds
bulkCopy.DestinationTableName = "<tableName>";
bulkCopy.WriteToServer(table);
}
If the column names are no the same, a dictionary to lookup the different names could be used.
To keep it simple for maintenance purpose, I went with a switch case sigh. However, I wrote a small script to add all those fields values to the table object.
I have a Table named Dummywith marks and student id (3 mark fields are there). I have another one table Applicantdetails this table also contains mark fields. what I want to do is I want to updates Dummy tables marks to Applicantdetails table's marks as per student id. I want to do this by mssql Storedprocedure. Any way to achieve it. If we write in code wise it should be like this
qry="select Applicantid,mark1,mark2,mark3 from Dummy"
//saved result to Datatable dt
foreaach(DataRow. rows in dt.rows)
{
string id=Convert.ToString(row["ApplicantID"].tostring();
string mark1=Convert.ToString(row["ApplicantID"].tostring();
string mark2=Convert.ToString(row["ApplicantID"].tostring();
string mark3=Convert.ToString(row["ApplicantID"].tostring();
qry="update Applicantdetails set Mark1=mark1,Mark2=Mark2,Mark3=Mark3
where ApplicantID=id";
}
This format I want to bring in storedprocedure..Please help me
Your Stored procedure would receive #applicationid ? Otherwise it would update all, Create a stored procedure with the following SQL
UPDATE A
SET Mark1= d.mark1, Mark2 = d.mark2, Mark3= d.mark3
FROM ApplicationDetail A
JOIN Dummy d on d.Applicationid = A.Applicationid
I need to generate a student number as the formula below with ASP.NET.
So every time a student is added to the database it should automatically generate a student ID.
NOTE( when adding a new student to the database I need to know the last student ID that has been added to the database so it can follow the correct formula).
RS 1011000
RS 1011001
RS 1011002
RS 1011003
RS 1011004
Create an id column as bigint identity(10000000, 1) and a calculated column which prefixes 'RS' to that column.
So you would get something like
Create table example (studentId bigint not null identity(10000000, 1),
RsNumber as 'RS' + CAST(studentId as varchar(15)))
http://www.kodyaz.com/articles/sql-server-computed-column-calculated-column-sample.aspx
I am working with C# Window Form, I have created a form connect to mySQL database and it display list of databases, list of tables on each database and also tables contents of each table.
Questions that I have here:
After I selected a random cell in the table (datagridview) and click Delete button, I want that row (corresponding to the selected cell) to be deleted on the database.
I also need that the datagridview table content also will be refreshed and updated (with that row has been removed). (This part I think I can do if I know how to do the part 1)
So I need help with the question 1, one of those things I can't not figure out is that how can I write the SQL statement to put in the SQLadapter or SQLcommandbuilder or whatever it is. I know the SQL statement should be like:
Delete from (selected Table) Where (THIS IS THE PART WHERE I STUCK AT) => I dont know what to put in this condition, how to get it?
Any helps and advises is really appreciated!
The delete statement should consider all the selected table primary key columns and the selected row from the datagridview.
How to get the primary key columns:
SELECT `COLUMN_NAME`
FROM `information_schema`.`COLUMNS`
WHERE (`TABLE_SCHEMA` = 'dbName')
AND (`TABLE_NAME` = 'tableName')
AND (`COLUMN_KEY` = 'PRI');
Source: A better way to get Primary Key columns
How your delete statement should look like:
DELETE FROM <TABLE>
WHERE <PRIMARY_KEY_COLUMN_1> = <ROW_VALUE_1>
AND <PRIMARY_KEY_COLUMN_2> = <ROW_VALUE_2>
You see, the table could have multiple columns uniquely identifying a row. There is also the possibility of existing a reference for that very row on another table, which would prevent you from deleting it.
It would look like this:
List<string> primaryKeyColumns = GetPrimaryKeyColumns(SelectedDB, SelectedTable);
string deleteWhereClause = string.Empty;
foreach (string column in primaryKeyColumns)
{
DataGridViewRow row = datagridview.CurrentCell.OwningRow;
string value = row.Cells[column].Value.ToString();
if (string.IsNullOrEmpty(deleteWhereClause))
{
deleteWhereClause = string.Concat(column, "=", value);
}
else
{
deleteWhereClause += string.Concat(" AND ", column, "=", value);
}
}
string deleteStatement = string.Format("DELETE FROM {0} WHERE {1}", SelectedTable, deleteWhereClause);
The method GetPrimaryKeyColumns returns the names of all the primary key columns of the selected table using the select statement i posted.
You would also have to deal with other types of columns such as dates and strings, but that's basically what you will have.