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using System;
using System.Collections;
using System.Collections.Specialized;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Runtime.InteropServices;
using System.Windows.Forms;
namespace DAL
{
public class DataControl
{
public static string connectionString = "server=" + SystemSet.getServerSet_ServerIP() + ";uid=" + SystemSet.getServerSet_ServerUser() + ";pwd=" + SystemSet.getServerSet_ServerPass() + ";database=" + SystemSet.getServerSet_ServerDataBase() + "";
/// <summary>
/// ³õʼ»¯ /// </summary>
public DataControl()
{
}
/// <summary>
/// ÎÞ²ÎÊý£¬²âÊÔÊý¾Ý¿âÁ¬½ÓÊÇ·ñÉèÖúÏÀí¡£ /// </summary>
/// <returns>ÊÇ·ñÁ¬½Ó³É¹¦</returns>
public static bool checkconn()
{
try
{
SqlConnection conn = new SqlConnection(connectionString);
conn.Open();
return true;
}
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constraint Example:
1. grammer:
create table [schema.]table
(column datatype [DEFAULT expr]
[column_constraint], ...
[table_constraint] [,......]);
2. example of a column_level constraint:
create table empl ......
Group functions
SELECT [column,] group_function(column) ... from table [WHERE condition] [GROUP BY group_by_expression] [ORDER BY column];
e.g.:
SELECT department_id, job_id, SUM(salary), COUNT(employee_id) from employees GROUP BY department_id, job_id ;
SELECT [column,] group_function(column).. ......
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WAITFOR
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WAITFOR { DELAY 'time' | TIME
'time' }
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DELAY
ָʾ Microsoft® SQL Server™ Ò»Ö±µÈµ½Ö¸¶¨µÄʱ¼ä¹ýÈ¥£¬×¿É´ï 24 Сʱ¡£
'time'
ÒªµÈ´ýµÄʱ¼ä¡£¿ÉÒÔ°´ datetime Êý¾Ý¿É½ÓÊܵĸñʽָ¶¨
time£¬Ò²¿ÉÒÔÓþֲ¿±äÁ¿Ö¸¶ ......