如果恢复失败，任何对
SQLGetConnectAttr(SQL_COPT_SS_CONNECTION_DEAD)
的调用都必须返回
SQL_CD_TRUE
。
在服务器上执行命令的任何函数都会返回以下状态代码：
Message
IMC01
The connection is broken and recovery is not possible. The client driver attempted to recover the connection one or more times and all attempts failed. Increase the value of ConnectRetryCount to increase the number of recovery attempts.
IMC02
The server did not acknowledge a recovery attempt, connection recovery is not possible.
IMC03
The server did not preserve the exact client TDS version requested during a recovery attempt, connection recovery is not possible.
IMC04
The server did not preserve the exact server major version requested during a recovery attempt, connection recovery is not possible.
IMC05
The connection is broken and recovery is not possible. The connection is marked by the server as unrecoverable. No attempt was made to restore the connection.
IMC06
The connection is broken and recovery is not possible. The connection is marked by the client driver as unrecoverable. No attempt was made to restore the connection.
以下示例包含两个函数。
func1
演示如何通过一个数据源名称 (DSN) 建立连接，该名称使用 Windows 上的 ODBC Driver for SQL Server。 DSN 使用 SQL Server 身份验证，并指定用户 ID。 然后，
func1
使用
SQL_COPT_SS_CONNECT_RETRY_COUNT
来检索连接重试次数。
func2
使用
SQLDriverConnect
、
ConnectRetryCount
连接字符串关键字和连接属性，检索连接重试和重试间隔的设置。
// Connection_resiliency.cpp
// compile with: odbc32.lib
#include <windows.h>
#include <stdio.h>
#include <sqlext.h>
#include <msodbcsql.h>
void func1() {
SQLHENV henv;
SQLHDBC hdbc;
SQLHSTMT hstmt;
SQLRETURN retcode;
SQLSMALLINT i = 21;
// Allocate environment handle
retcode = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &henv);
// Set the ODBC version environment attribute
if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
retcode = SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION, (void*)SQL_OV_ODBC3, 0);
// Allocate connection handle
if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
retcode = SQLAllocHandle(SQL_HANDLE_DBC, henv, &hdbc);
// Set login timeout to 5 seconds
if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
SQLSetConnectAttr(hdbc, SQL_LOGIN_TIMEOUT, (SQLPOINTER)5, 0);
// Connect to data source
retcode = SQLConnect(hdbc, (SQLCHAR*)"MyDSN", SQL_NTS, (SQLCHAR*)"userID", SQL_NTS, (SQLCHAR*)"password_for_userID", SQL_NTS);
retcode = SQLGetConnectAttr(hdbc, SQL_COPT_SS_CONNECT_RETRY_COUNT, &i, SQL_IS_INTEGER, NULL);
// Allocate statement handle
if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
retcode = SQLAllocHandle(SQL_HANDLE_STMT, hdbc, &hstmt);
// Process data
if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
SQLFreeHandle(SQL_HANDLE_STMT, hstmt);
SQLDisconnect(hdbc);
SQLFreeHandle(SQL_HANDLE_DBC, hdbc);
SQLFreeHandle(SQL_HANDLE_ENV, henv);
void func2() {
SQLHENV henv;
SQLHDBC hdbc1;
SQLHSTMT hstmt;
SQLRETURN retcode;
SQLSMALLINT i = 21;
#define MAXBUFLEN 255
SQLCHAR ConnStrIn[MAXBUFLEN] = "DRIVER={ODBC Driver 18 for SQL Server};SERVER=server_that_supports_connection_resiliency;Encrypt=yes;UID=userID;PWD= password_for_userID;ConnectRetryCount=2";
SQLCHAR ConnStrOut[MAXBUFLEN];
SQLSMALLINT cbConnStrOut = 0;
// Allocate environment handle
retcode = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &henv);
// Set the ODBC version environment attribute
if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
retcode = SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION, (SQLPOINTER*)SQL_OV_ODBC3_80, SQL_IS_INTEGER);
// Allocate connection handle
if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
retcode = SQLAllocHandle(SQL_HANDLE_DBC, henv, &hdbc1);
// Set login timeout to 5 seconds
if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {
// SQLSetConnectAttr(hdbc1, SQL_LOGIN_TIMEOUT, (SQLPOINTER)5, 0);
retcode = SQLDriverConnect(hdbc1, NULL, ConnStrIn, SQL_NTS, NULL, 0, NULL, SQL_DRIVER_NOPROMPT);
retcode = SQLGetConnectAttr(hdbc1, SQL_COPT_SS_CONNECT_RETRY_COUNT, &i, SQL_IS_INTEGER, NULL);
retcode = SQLGetConnectAttr(hdbc1, SQL_COPT_SS_CONNECT_RETRY_INTERVAL, &i, SQL_IS_INTEGER, NULL);
int main() {
func1();
func2();
Microsoft ODBC Driver for SQL Server
