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11-Mavzu: ado. Net texnologiyasi. Reja: ado. Net asoslari ado. Net oby’ekt va sinflari
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| bet | 14/14 | | Sana | 14.06.2023 | | Hajmi | 0.51 Mb. | | #72848 |
Bog'liq 11-Mavzu ado. Net texnologiyasi. Reja ado. Net asoslari ado. N anatomiya cheloveka, Reference-375201101921 , 8-ma\'ruza, kamola slayd, 1 mavzu, Amaliy matematika mustaqil ta\'lim, 003 O\'zbekiston tarixi O\'zbek modeli 3 dars 2kurs, The-College-Panda-Sat-Math-, Ergashov Oybek, Mavzu, Principles of. ni mundarijasi uzb, chuvstvitelnye-elementy-vysokotemperaturnyh-datchikov-davleniya-materialy-i-tehnologii-izgotovleniya, tehnologiya-izgotovleniya-poluprovodnikovogo-chuvstvitelnogo-elementa-datchika-davleniya-na-osnove-polikristallicheskogo-almaza, primenenie-uravneniy-eylera-lagranzha-k-resheniyu-zadachi-dinamiki-sistemy-most-poezd, Pedagogik amaliyot kundalik daftariOb'ekt yangilanishi. Yangilanish xuddi shu tarzda amalga oshiriladi, endi faqat quyidagi sintaksisga ega bo'lgan UPDATE sql ifodasi ishlatiladi:
UPDATE jadval_nomi
SET ustun1=qiymat1, ustun2=qiymat2, ustunN=qiymatN
WHERE ba'zi ustun = ba'zi qiymat
Ushbu iborani qo'llaymiz:
string connectionString = @"Data Source=.\SQLEXPRESS;Initial Catalog=usersdb;Integrated Security=True";
string sqlExpression = "UPDATE Users SET Age=20 WHERE Name='Tom'";
using (SqlConnection connection = new SqlConnection(connectionString)) {
connection.Open();
SqlCommand command = new SqlCommand(sqlExpression, connection);
int number = command.ExecuteNonQuery();
Console.WriteLine("Обновлено объектов: {0}", number);
}
Bu erda satr yangilanadi, unda Name = Tom, ya'ni yuqoridagi ob'ekt qo'shiladi. Agar jadvalda Name = Tom bo'lgan bir nechta satrlar bo'lsa, unda bu satrlarning barchasi yangilanadi.
Olib tashlash. O'chirish quyidagi sintaksisga ega bo'lgan sql DELETE ifodasi yordamida amalga oshiriladi:
DELETE FROM jadval
WHERE ustun = qiymati
Masalan, Tom ismli barcha foydalanuvchilarni yo'q qiling.
string connectionString = @"Data Source=.\SQLEXPRESS;Initial Catalog=usersdb;Integrated Security=True";
string sqlExpression = "DELETE FROM Users WHERE Name='Tom'";
using (SqlConnection connection = new SqlConnection(connectionString))
{
connection.Open();
SqlCommand command = new SqlCommand(sqlExpression, connection);
int number = command.ExecuteNonQuery();
Console.WriteLine("Удалено объектов: {0}", number);
}
Uchala holatda ham faqat sql ifodasi haqiqatan ham o'zgaradi va qolgan mantiq o'zgarishsiz qoladi. Va biz bir vaqtning o'zida bir nechta operatsiyalarni bajarishimiz mumkin:
static void Main(string[] args)
{
string connectionString = @"Data Source=.\SQLEXPRESS;Initial Catalog=usersdb;Integrated Security=True";
Console.WriteLine("Введите имя:");
string name = Console.ReadLine();
Console.WriteLine("Введите возраст:");
int age = Int32.Parse(Console.ReadLine());
string sqlExpression = String.Format("INSERT INTO Users (Name, Age) VALUES ('{0}', {1})", name, age);
using (SqlConnection connection = new SqlConnection(connectionString))
{
connection.Open();
// добавление
SqlCommand command = new SqlCommand(sqlExpression, connection);
int number = command.ExecuteNonQuery();
Console.WriteLine("Добавлено объектов: {0}", number);
// обновление ранее добавленного объекта
Console.WriteLine("Введите новое имя:");
name = Console.ReadLine();
sqlExpression = String.Format("UPDATE Users SET Name='{0}' WHERE Age={1}", name, age);
command.CommandText = sqlExpression;
number = command.ExecuteNonQuery();
Console.WriteLine("Обновлено объектов: {0}", number);
}
Console.Read();
}
Konsol chiqishi:
Adabiyotlar
1. Карли Уотсонб Кристиан Нейгелб Якоб Хаммаер Педерсенб Джон Д Рид, Морган Скиннер, Эрик Уайт. Visual С# 2008: базовый курс.: Пер. с англ. М.: ООО "И.Д. Вилямс ". 2009. 1216 с.
2.Неш Трей. С # 2010: ускоренный курс для профессионалов.: Пер. с англ. М.: ООО "И.Д. Вилямс ". 2010.
3. https://docs.microsoft.com/ru-ru/dotnet/api/system.data?view=netframework-4.8
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