获取SQL server数据库中所有表的数据 C++实现

要获取 SQL Server 数据库中所有表的数据，你可以使用 C++ 中的 ODBC API。下面是一个简单的示例代码，它会连接到一个 SQL Server 数据库，获取所有表的名称，然后针对每个表执行一个 SELECT 查询，以获取表中的所有数据。

#include <iostream>
#include <windows.h>
#include <sqlext.h>
#include <sqltypes.h>
#include <sql.h>

void showError(SQLHANDLE handle, SQLSMALLINT type) {
    SQLCHAR SqlState[6], SQLStmt[100], Msg[SQL_MAX_MESSAGE_LENGTH];
    SQLINTEGER    NativeError;
    SQLSMALLINT   MsgLen;
    SQLGetDiagRec(type, handle, 1, SqlState, &NativeError, Msg, sizeof(Msg), &MsgLen);
    std::cerr << "SQL Error " << NativeError << " (" << SqlState << "): " << Msg << std::endl;
}

int main() {
    SQLHENV env;
    SQLHDBC dbc;
    SQLHSTMT stmt;
    SQLRETURN ret;

    // Allocate an environment handle
    SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &env);
    SQLSetEnvAttr(env, SQL_ATTR_ODBC_VERSION, (void*)SQL_OV_ODBC3, 0);

    // Allocate a connection handle
    SQLAllocHandle(SQL_HANDLE_DBC, env, &dbc);

    // Connect to the database
    ret = SQLConnect(dbc, (SQLCHAR*)"MyDatabase", SQL_NTS, (SQLCHAR*)"MyUsername", SQL_NTS, (SQLCHAR*)"MyPassword", SQL_NTS);
    if (ret != SQL_SUCCESS && ret != SQL_SUCCESS_WITH_INFO) {
        showError(dbc, SQL_HANDLE_DBC);
        return 1;
    }

    // Allocate a statement handle
    SQLAllocHandle(SQL_HANDLE_STMT, dbc, &stmt);

    // Get the list of tables in the database
    ret = SQLTables(stmt, NULL, 0, NULL, 0, (SQLCHAR*)"dbo", SQL_NTS, (SQLCHAR*)"TABLE", SQL_NTS);
    if (ret != SQL_SUCCESS && ret != SQL_SUCCESS_WITH_INFO) {
        showError(stmt, SQL_HANDLE_STMT);
        return 1;
    }

    // Fetch the results of the query
    SQLCHAR tableName[256];
    while (SQLFetch(stmt) == SQL_SUCCESS) {
        SQLGetData(stmt, 3, SQL_C_CHAR, tableName, sizeof(tableName), NULL);
        std::cout << "Table: " << tableName << std::endl;

        // Execute a SELECT query on the table
        SQLCHAR query[256];
        sprintf_s((char*)query, sizeof(query), "SELECT * FROM %s", tableName);
        ret = SQLExecDirect(stmt, query, SQL_NTS);
        if (ret != SQL_SUCCESS && ret != SQL_SUCCESS_WITH_INFO) {
            showError(stmt, SQL_HANDLE_STMT);
            return 1;
        }

        // Fetch the results of the query
        SQLCHAR columnValue[256];
        SQLSMALLINT numColumns;
        SQLNumResultCols(stmt, &numColumns);
        while (SQLFetch(stmt) == SQL_SUCCESS) {
            for (int i = 1; i <= numColumns; i++) {
                SQLGetData(stmt, i, SQL_C_CHAR, columnValue, sizeof(columnValue), NULL);
                std::cout << columnValue << " ";
            }
            std::cout << std::endl;
        }
    }

    // Free the statement handle
    SQLFreeHandle(SQL_HANDLE_STMT, stmt);

    // Disconnect from the database
    SQLDisconnect(dbc);

    // Free the connection handle
    SQLFreeHandle(SQL_HANDLE_DBC, dbc);

    // Free the environment handle
    SQLFreeHandle(SQL_HANDLE_ENV, env);

    return 0;
}

注意：在此示例代码中，数据库名称为 "MyDatabase"，用户名为 "MyUsername"，密码为 "MyPassword"。你需要将这些值替换为你自己的数据库凭据。