» Công Nghệ Thông Tin

» Kỹ thuật lập trình

Adding Tables to a Database

Chia sẻ: Bui Tuan | Ngày: | Loại File: PDF | Số trang:3

0

Báo xấu

74
lượt xem 5
download

Adding Tables to a Database

Mô tả tài liệu

Download Vui lòng tải xuống để xem tài liệu đầy đủ

[ Team LiB ] Recipe 10.8 Adding Tables to a Database Problem You need to add a table to an existing database. Solution Use the CREATE TABLE statement. The sample code executes the DDL statement—using the ExecuteNonQuery( ) method of the Command object—to add a table to an existing SQL Server database.

Chủ đề:

Bình luận(0) Đăng nhập để gửi bình luận!

Lưu

Nội dung Text: Adding Tables to a Database

[ Team LiB ] Recipe 10.8 Adding Tables to a Database Problem You need to add a table to an existing database. Solution Use the CREATE TABLE statement. The sample code executes the DDL statement—using the ExecuteNonQuery( ) method of the Command object—to add a table to an existing SQL Server database. The C# code is shown in Example 10-8. Example 10-8. File: AddTableToDatabaseForm.cs // Namespaces, variables, and constants using System; using System.Configuration; using System.Data; using System.Data.SqlClient; // . . . SqlConnection conn = new SqlConnection( ConfigurationSettings.AppSettings["Sql_ConnectString"]); String createSql = "CREATE TABLE MyTable " + "(MyTableId int IDENTITY(1,1) PRIMARY KEY CLUSTERED)"; SqlCommand cmd = new SqlCommand(createSql, conn); // Create the table in the database. try { conn.Open( ); cmd.ExecuteNonQuery( ); resultTextBox.Text = "Table created successfully"; } catch (System.Exception ex) {
resultTextBox.Text = ex.ToString( ); } finally { if (conn.State == ConnectionState.Open) conn.Close( ); } Discussion There are two categories of SQL statements: Database Definition Language (DDL) Used to manage all objects in the database, generally with CREATE, ALTER, and DROP statements to create, modify, and delete objects, respectively. These statements generally require DBA permissions to execute. Database Management Language (DML) Used to manipulate—select, insert, update, and delete—data in the database objects. Database objects are defined using DDL. The solution executes a DDL CREATE TABLE statement to create a table in the database and a primary key on the new table in a SQL Server database. You can programmatically drop a table using the DROP TABLE statement in a similar way. To drop the table created in this example, use the following code: DROP TABLE MyTable The DROP TABLE statement will fail if the table is in use; therefore, it might be necessary to restart the SQL Server. For more information about the CREATE TABLE statement or the DROP TABLE statement, see Microsoft SQL Server Books Online. The solution for Oracle databases and other databases is similar to that shown for SQL Server. However, the DDL syntax for each database varies slightly because of differences in database server capabilities and architecture. For example, the CREATE TABLE statement for Oracle is different because Oracle does not support identity columns and uses sequences instead (see Recipe 4.4 for more information about Oracle sequences). For more information about Oracle SQL syntax, see Oracle in a Nutshell by Rick Greenwald and David C. Kreines (O'Reilly).
[ Team LiB ]

CÓ THỂ BẠN MUỐN DOWNLOAD

CEO.13: Bộ Tài Liệu Hệ Thống Mô Tả Công Việc Dành Cho Nhân Viên IT

121 tài liệu

1978 lượt tải

THÔNG TIN

TRỢ GIÚP

HỖ TRỢ KHÁCH HÀNG

Theo dõi chúng tôi

Chịu trách nhiệm nội dung:

Nguyễn Công Hà - Giám đốc Công ty TNHH TÀI LIỆU TRỰC TUYẾN VI NA

LIÊN HỆ

Địa chỉ: P402, 54A Nơ Trang Long, Phường 14, Q.Bình Thạnh, TP.HCM

Hotline:0933030098

Email: support@vdoc.com.vn

Giấy phép Mạng Xã Hội số: 670/GP-BTTTT cấp ngày 30/11/2015 Copyright © 2009-2019 TaiLieu.VN. All rights reserved.