ADO.NET lets you run any SQL against your database. Here’s how to do basic CRUD (Create, Read, Update, Delete).
🔍 SELECT (Read Data)
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| string sql = "SELECT Id, Name FROM Users";
using (SqlCommand cmd = new SqlCommand(sql, conn))
using (SqlDataReader reader = cmd.ExecuteReader())
{
while (reader.Read())
Console.WriteLine($"{reader["Id"]}: {reader["Name"]}");
}
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➕ INSERT (Add Data)
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| string sql = "INSERT INTO Users (Name) VALUES (@name)";
using (SqlCommand cmd = new SqlCommand(sql, conn))
{
cmd.Parameters.AddWithValue("@name", "Bob");
cmd.ExecuteNonQuery();
}
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✏️ UPDATE (Modify Data)
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| string sql = "UPDATE Users SET Name = @name WHERE Id = @id";
using (SqlCommand cmd = new SqlCommand(sql, conn))
{
cmd.Parameters.AddWithValue("@name", "Charlie");
cmd.Parameters.AddWithValue("@id", 1);
cmd.ExecuteNonQuery();
}
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🗑️ DELETE (Remove Data)
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| string sql = "DELETE FROM Users WHERE Id = @id";
using (SqlCommand cmd = new SqlCommand(sql, conn))
{
cmd.Parameters.AddWithValue("@id", 1);
cmd.ExecuteNonQuery();
}
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⚠️ Always Use Parameters
- Prevents SQL injection
- Handles data types safely
Next: Introduction to Entity Framework!
