【发布时间】：2008-09-30 14:40:31
【问题描述】：
我编写了以下代码，但 SQLBindCol 似乎无法正常工作（当然我也可能把整个程序搞砸了！）连接有效，它在数据库中创建表，添加记录很好，它们在 SQL 企业管理器中看起来都很好。所以我需要帮助是在评论“第 3 部分和第 4 部分：基于条件的搜索”之后。也许我应该以完全不同的方式完成这项任务，或者这是一种可接受的方法？
#include <iostream>
#include <cstdio>
#include <string>
#include <windows.h>
#include <sql.h>
#include <sqlext.h>
#include <sqltypes.h>
using namespace std; // to save us having to type std::
const int MAX_CHAR = 1024;
int main ( )
{
SQLCHAR SQLStmt[MAX_CHAR];
char strSQL[MAX_CHAR];
char chrTemp;
SQLVARCHAR rtnFirstName[50];
SQLVARCHAR rtnLastName[50];
SQLVARCHAR rtnAddress[30];
SQLVARCHAR rtnCity[30];
SQLVARCHAR rtnState[3];
SQLDOUBLE rtnSalary;
SQLVARCHAR rtnGender[1];
SQLINTEGER rtnAge;
// Get a handle to the database
SQLHENV EnvironmentHandle;
RETCODE retcode = SQLAllocHandle( SQL_HANDLE_ENV, SQL_NULL_HANDLE, &EnvironmentHandle );
// Set the SQL environment flags
retcode = SQLSetEnvAttr( EnvironmentHandle, SQL_ATTR_ODBC_VERSION, (SQLPOINTER) SQL_OV_ODBC3, SQL_IS_INTEGER );
// create handle to the SQL database
SQLHDBC ConnHandle;
retcode = SQLAllocHandle( SQL_HANDLE_DBC, EnvironmentHandle, &ConnHandle );
// Open the database using a System DSN
retcode = SQLDriverConnect(ConnHandle,
NULL,
(SQLCHAR*)"DSN=PRG411;UID=myUser;PWD=myPass;",
SQL_NTS,
NULL,
SQL_NTS,
NULL,
SQL_DRIVER_NOPROMPT);
if (!retcode)
{
cout << "SQLConnect() Failed";
}
else
{
// create a SQL Statement variable
SQLHSTMT StatementHandle;
retcode = SQLAllocHandle(SQL_HANDLE_STMT, ConnHandle, &StatementHandle);
// Part 1: Create the Employee table (Database)
do
{
cout << "Create the new table? ";
cin >> chrTemp;
} while (cin.fail());
if (chrTemp == 'y' || chrTemp == 'Y')
{
strcpy((char *) SQLStmt, "CREATE TABLE [dbo].[Employee]([pkEmployeeID] [int] IDENTITY(1,1) NOT NULL,[FirstName] [varchar](50) NOT NULL,[LastName] [varchar](50) NOT NULL,[Address] [varchar](30) NOT NULL,[City] [varchar](30) NOT NULL,[State] [varchar](3) NOT NULL, [Salary] [double] NOT NULL,[Gender] [varchar](1) NOT NULL, [Age] [int] NOT NULL, CONSTRAINT [PK_Employee] PRIMARY KEY CLUSTERED ([pkEmployeeID] ASC)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]) ON [PRIMARY]");
retcode = SQLExecDirect(StatementHandle, SQLStmt, SQL_NTS);
}
// Part 2: Hardcode records into the table
do
{
cout << "Add records to the table? ";
cin >> chrTemp;
} while (cin.fail());
if (chrTemp == 'y' || chrTemp == 'Y')
{
strcpy((char *) SQLStmt, "INSERT INTO employee([FirstName], [LastName], [Address], [City], [State], [Salary], [Gender],[Age]) VALUES ('Mike','Slentz','123 Torrey Dr.','North Clairmont','CA', 48000.00 ,'M',34)");
retcode = SQLExecDirect(StatementHandle, SQLStmt, SQL_NTS);
strcpy((char *) SQLStmt, "INSERT INTO employee([FirstName], [LastName], [Address], [City], [State], [Salary], [Gender],[Age]) VALUES ('Sue','Vander Hayden','46 East West St.','San Diego','CA', 36000.00 ,'F',28)");
retcode = SQLExecDirect(StatementHandle, SQLStmt, SQL_NTS);
strcpy((char *) SQLStmt, "INSERT INTO employee([FirstName], [LastName], [Address], [City], [State], [Salary], [Gender],[Age]) VALUES ('Sharon','Stonewall','756 West Olive Garden Way','Plymouth','MA', 56000.00 ,'F',58)");
retcode = SQLExecDirect(StatementHandle, SQLStmt, SQL_NTS);
strcpy((char *) SQLStmt, "INSERT INTO employee([FirstName], [LastName], [Address], [City], [State], [Salary], [Gender],[Age]) VALUES ('James','Bartholemew','777 Praying Way','Falls Church','VA', 51000.00 ,'M',45)");
retcode = SQLExecDirect(StatementHandle, SQLStmt, SQL_NTS);
strcpy((char *) SQLStmt, "INSERT INTO employee([FirstName], [LastName], [Address], [City], [State], [Salary], [Gender],[Age]) VALUES ('Joe','Smith','111 North 43rd Ave','Peoria','AZ', 44000.00 ,'M', 40)");
retcode = SQLExecDirect(StatementHandle, SQLStmt, SQL_NTS);
strcpy((char *) SQLStmt, "INSERT INTO employee([FirstName], [LastName], [Address], [City], [State], [Salary], [Gender],[Age]) VALUES ('Michael','Smith','20344 North Swan Park','Phoenix','AZ', 24000.00 ,'M', 40)");
retcode = SQLExecDirect(StatementHandle, SQLStmt, SQL_NTS);
strcpy((char *) SQLStmt, "INSERT INTO employee([FirstName], [LastName], [Address], [City], [State], [Salary], [Gender],[Age]) VALUES ('Jennifer','Jones','123 West North Ave','Flagstaff','AZ', 40000.00 ,'F', 40)");
retcode = SQLExecDirect(StatementHandle, SQLStmt, SQL_NTS);
strcpy((char *) SQLStmt, "INSERT INTO employee([FirstName], [LastName], [Address], [City], [State], [Salary], [Gender],[Age]) VALUES ('Cora','York','33rd Park Way Drive','Mayville','MI', 30000.00 ,'F', 61)");
retcode = SQLExecDirect(StatementHandle, SQLStmt, SQL_NTS);
strcpy((char *) SQLStmt, "INSERT INTO employee([FirstName], [LastName], [Address], [City], [State], [Salary], [Gender],[Age]) VALUES ('Tom','Jefferson','234 Friendship Way','Battle Creek','MI', 41000.00 ,'M', 31)");
retcode = SQLExecDirect(StatementHandle, SQLStmt, SQL_NTS);
}
// Part 3 & 4: Searchs based on criteria
do
{
cout << "1. Display all records in the database" << endl;
cout << "2. Display all records with age greater than 40" << endl;
cout << "3. Display all records with salary over $30K" << endl;
cout << "4. Exit" << endl << endl;
do
{
cout << "Please enter a selection: ";
cin >> chrTemp;
} while (cin.fail());
if (chrTemp == '1')
{
strcpy((char *) SQLStmt, "SELECT [FirstName], [LastName], [Address], [City], [State], [Salary], [Gender],[Age] FROM EMPLOYEE");
}
else if (chrTemp == '2')
{
strcpy((char *) SQLStmt, "SELECT [FirstName], [LastName], [Address], [City], [State], [Salary], [Gender],[Age] FROM EMPLOYEE WHERE [AGE] > 40");
}
else if (chrTemp == '3')
{
strcpy((char *) SQLStmt, "SELECT [FirstName], [LastName], [Address], [City], [State], [Salary], [Gender],[Age] FROM EMPLOYEE WHERE [Salary] > 30000");
}
if (chrTemp == '1' || chrTemp == '2' || chrTemp == '3')
{
retcode = SQLExecDirect(StatementHandle, SQLStmt, SQL_NTS);
SQLBindCol(StatementHandle, 1, SQL_C_CHAR, &rtnFirstName, sizeof(rtnFirstName), NULL );
SQLBindCol(StatementHandle, 2, SQL_C_CHAR, &rtnLastName, sizeof(rtnLastName), NULL );
SQLBindCol(StatementHandle, 3, SQL_C_CHAR, &rtnAddress, sizeof(rtnAddress), NULL );
SQLBindCol(StatementHandle, 4, SQL_C_CHAR, &rtnCity, sizeof(rtnCity), NULL );
SQLBindCol(StatementHandle, 5, SQL_C_CHAR, &rtnState, sizeof(rtnState), NULL );
SQLBindCol(StatementHandle, 6, SQL_C_DOUBLE, &rtnSalary, sizeof(rtnSalary), NULL );
SQLBindCol(StatementHandle, 7, SQL_C_CHAR, &rtnGender, sizeof(rtnGender), NULL );
SQLBindCol(StatementHandle, 8, SQL_C_NUMERIC, &rtnAge, sizeof(rtnAge), NULL );
for(;;)
{
retcode = SQLFetch(StatementHandle);
if (retcode == SQL_NO_DATA_FOUND) break;
cout << rtnFirstName << " " << rtnLastName << " " << rtnAddress << " " << rtnCity << " " << rtnState << " " << rtnSalary << " " << rtnGender << "" << rtnAge << endl;
}
}
} while (chrTemp != '4');
SQLFreeStmt(StatementHandle, SQL_CLOSE );
SQLFreeConnect(ConnHandle);
SQLFreeEnv(EnvironmentHandle);
printf( "Done.\n" );
}
return 0;
}
【问题讨论】：
-
if(!retcode) 应该是 if(retcode != SQL_SUCCESS && retcode != SQL_SUCCESS_WITH_INFO)