In C#, you can upload an Excel sheet and import the data into a SQL Server database using the OpenXml library to read the contents of the Excel sheet, and System.Data.SqlClient to insert the data into the database. Here's an example:
using System;
using System.Data;
using System.Data.SqlClient;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Spreadsheet;
public static void UploadExcelAndImportToSql(string connectionString, string excelFilePath, string tableName)
{
// Open the Excel sheet
using (var document = SpreadsheetDocument.Open(excelFilePath, false))
{
// Get the first worksheet
var worksheetPart = document.WorkbookPart.WorksheetParts.First();
var sheetData = worksheetPart.Worksheet.Elements<SheetData>().First();
// Get the header row and column count
var headerRow = sheetData.Elements<Row>().First();
var columnCount = headerRow.Elements<Cell>().Count();
// Create a SQL connection and command
using (var connection = new SqlConnection(connectionString))
using (var command = new SqlCommand($"INSERT INTO {tableName} VALUES ({new string('?', columnCount).TrimEnd(',')})", connection))
{
connection.Open();
// Iterate over the rows and insert data into the SQL database
foreach (var row in sheetData.Elements<Row>().Skip(1))
{
for (var i = 0; i < columnCount; i++)
{
var cell = row.Elements<Cell>().ElementAt(i);
var cellValue = GetCellValue(document, cell);
// Set the parameter value
command.Parameters.AddWithValue($"@{i}", cellValue);
}
// Execute the SQL command
command.ExecuteNonQuery();
}
}
}
}
private static string GetCellValue(SpreadsheetDocument document, Cell cell)
{
if (cell.DataType == null)
{
return cell.InnerText;
}
switch (cell.DataType.Value)
{
case CellValues.SharedString:
return document.WorkbookPart.SharedStringTablePart.SharedStringTable.ElementAt(int.Parse(cell.InnerText)).InnerText;
case CellValues.Boolean:
return cell.InnerText == "1" ? "TRUE" : "FALSE";
default:
return cell.InnerText;
}
}
In this example, the UploadExcelAndImportToSql method takes a connection string, an Excel file path, and a table name as input parameters. The method opens the Excel sheet using the SpreadsheetDocument class from the OpenXml library and gets the first worksheet and its data. The method also creates a SQL connection and command using the specified connection string and table name.
The method then iterates over the rows in the worksheet and inserts the data into the SQL database. For each row, the method iterates over the cells and gets the cell value using the GetCellValue method, which handles different cell data types (string, shared string, boolean, etc.) as well as cell references to shared strings.
The method then sets the parameter values of the SQL command with the cell values and executes the command using the ExecuteNonQuery method.
Note that this example assumes that the first row of the Excel sheet contains column headers, and that the column order and names match the SQL table. You may need to modify the code to handle different Excel sheet formats or SQL table structures.
To insert data into SQL Server in C#, you can use the SqlCommand and SqlConnection classes in the System.Data.SqlClient namespace.
Here is an example that demonstrates how to insert data into a SQL Server database in C#:
using System.Data.SqlClient;
class Program
{
static void Main(string[] args)
{
var connectionString = "Data Source=ServerName;Initial Catalog=DatabaseName;User ID=UserName;Password=Password";
using (var connection = new SqlConnection(connectionString))
{
connection.Open();
var sql = "INSERT INTO Customers (FirstName, LastName, Email) VALUES (@FirstName, @LastName, @Email)";
using (var command = new SqlCommand(sql, connection))
{
command.Parameters.AddWithValue("@FirstName", "John");
command.Parameters.AddWithValue("@LastName", "Doe");
command.Parameters.AddWithValue("@Email", "[email protected]");
var rowsAffected = command.ExecuteNonQuery();
Console.WriteLine($"Rows affected: {rowsAffected}");
}
}
}
}
In this example, a connection string is defined that specifies the server name, database name, username, and password. A SqlConnection object is created using the connection string, and opened using the Open method.
Then, an SQL statement is defined that inserts data into a Customers table, which has columns for FirstName, LastName, and Email. A SqlCommand object is created using the SQL statement and the SqlConnection object. The AddWithValue method is used to add parameters to the command object, which correspond to the values to be inserted.
The ExecuteNonQuery method of the SqlCommand object is called to execute the SQL statement and insert the data into the database. The ExecuteNonQuery method returns the number of rows affected by the operation, which is printed to the console.
Note that this is just an example and you should customize it to suit your own data and table schema. Also, it is important to use parameterized queries to prevent SQL injection attacks.
When working with nullable DateTime values and databases in C#, you need to consider how to handle the mapping and storage of null values. Here are some approaches you can take:
Use a nullable DateTime (DateTime?) type: Declare your variable or property as DateTime? to indicate that it can hold null values. This allows you to explicitly represent missing or unknown dates. When storing this value in the database, the database column should be nullable as well.
Map to a nullable column in the database: Ensure that the corresponding column in the database is nullable, allowing it to store null values. Many database providers (such as SQL Server) support nullable columns, which align well with nullable types in C#. This allows you to directly map the nullable DateTime to the nullable column in the database.
Handle null values explicitly: When working with nullable DateTime values, make sure to handle null values appropriately in your code. You can use null-coalescing (??) or null-conditional (?.) operators to handle null checks and provide default values if necessary. For example:
DateTime? nullableDate = GetNullableDate(); // Use null-coalescing operator to provide a default value DateTime date = nullableDate ?? DateTime.MinValue; // Or use null-conditional operator for optional operations int? year = nullableDate?.Year;
Use database-specific handling: If you are using an ORM (Object-Relational Mapping) tool like Entity Framework, it may handle nullable DateTime values automatically. Ensure that the mapping configuration of the ORM is set appropriately to handle null values for the DateTime properties.
Consider database defaults or constraints: Depending on your requirements, you may choose to have database defaults or constraints that handle null values for the DateTime column. For example, you can set a default value of NULL or use constraints to enforce the presence of a value.
Remember to handle null values consistently throughout your application and database to avoid any unexpected behavior or inconsistencies.