示例代码：test

The following example demonstrates how to fetch data from a table using mysql_stmt_result_metadata(), mysql_stmt_bind_result(), and mysql_stmt_fetch().

CTSManager/CTSManager/Database.cpp

@@ -24,7 +24,7 @@ BOOL CDatabase::SetBinaryField(std::string strCondition, void* pDataIn, int nDat
 		MYSQL_BIND bind;
 		memset(&bind, 0, sizeof(MYSQL_BIND));
 		bind.buffer_type = MYSQL_TYPE_BLOB;
-		(*bind.length) = nDataLen;
+		(*bind.length) = nDataLen;	// 输出的长度;
 		memcpy(bind.buffer, pDataIn, nDataLen);
 		if (!mysql_stmt_bind_param(stmt, (MYSQL_BIND*)&bind))
 		{
@@ -206,18 +206,18 @@ BOOL CDatabase::InserSoc(const STSOC& soc)
 	//初始化参数
 	bind[0].buffer_type = MYSQL_TYPE_VARCHAR;
 	bind[0].buffer = (void*)soc.name.c_str();
+	bind[0].buffer_length = soc.name.size();
 	bind[0].is_null = 0;
-	*bind[0].length = soc.name.size();
 
 	bind[1].buffer_type = MYSQL_TYPE_VARCHAR;
 	bind[1].buffer = (void*)soc.provider.c_str();
+	bind[1].buffer_length = soc.provider.size();
 	bind[1].is_null = 0;
-	*bind[1].length = soc.provider.size();
 
 	bind[2].buffer_type = MYSQL_TYPE_VARCHAR;
 	bind[2].buffer = (void*)soc.note.c_str();
+	bind[2].buffer_length = soc.note.size();
 	bind[2].is_null = 0;
-	*bind[2].length = soc.note.size();
 
 	//绑定参数123
 	mysql_stmt_bind_param(stmt, bind);
@@ -274,22 +274,16 @@ BOOL CDatabase::InserSoc(std::string name, std::string provider, std::string not
 	bind[0].buffer = (void*)name.c_str();
 	bind[0].buffer_length = name.size();
 	bind[0].is_null = 0;
-	//bind[0].length = (unsigned long*)name.size();
-	bind[0].length = 0;
 
 	bind[1].buffer_type = MYSQL_TYPE_VARCHAR;
 	bind[1].buffer = (void*)provider.c_str();
 	bind[1].buffer_length = provider.size();
 	bind[1].is_null = 0;
-	//bind[1].length = (unsigned long*)provider.size();
-	bind[1].length = 0;
 
 	bind[2].buffer_type = MYSQL_TYPE_VARCHAR;
 	bind[2].buffer = (void*)note.c_str();
 	bind[2].buffer_length = note.size();
 	bind[2].is_null = 0;
-	//bind[2].length = (unsigned long*)note.size();
-	bind[2].length = 0;
 
 	//绑定参数123
 	if (0 != mysql_stmt_bind_param(stmt, bind))
@@ -756,3 +750,192 @@ BOOL CDatabase::QueryServer(std::vector<STServer>& vtServer)
 
 	return TRUE;
 }
+
+// 示例;
+void test(MYSQL* mysql)
+{
+#define STRING_SIZE 50
+
+#define SELECT_SAMPLE "SELECT col1, col2, col3, col4 \
+                       FROM test_table"
+
+	MYSQL_STMT* stmt;
+	MYSQL_BIND    bind[4];
+	MYSQL_RES* prepare_meta_result;
+	MYSQL_TIME    ts;
+	unsigned long length[4];
+	int           param_count, column_count, row_count;
+	short         small_data;
+	int           int_data;
+	char          str_data[STRING_SIZE];
+	my_bool       is_null[4];
+	my_bool       error[4];
+
+	/* Prepare a SELECT query to fetch data from test_table */
+	stmt = mysql_stmt_init(mysql);
+	if (!stmt)
+	{
+		fprintf(stderr, " mysql_stmt_init(), out of memory\n");
+		exit(0);
+	}
+	if (mysql_stmt_prepare(stmt, SELECT_SAMPLE, strlen(SELECT_SAMPLE)))
+	{
+		fprintf(stderr, " mysql_stmt_prepare(), SELECT failed\n");
+		fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
+		exit(0);
+	}
+	fprintf(stdout, " prepare, SELECT successful\n");
+
+	/* Get the parameter count from the statement */
+	param_count = mysql_stmt_param_count(stmt);
+	fprintf(stdout, " total parameters in SELECT: %d\n", param_count);
+
+	if (param_count != 0) /* validate parameter count */
+	{
+		fprintf(stderr, " invalid parameter count returned by MySQL\n");
+		exit(0);
+	}
+
+	/* Execute the SELECT query */
+	if (mysql_stmt_execute(stmt))
+	{
+		fprintf(stderr, " mysql_stmt_execute(), failed\n");
+		fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
+		exit(0);
+	}
+
+	/* Fetch result set meta information */
+	prepare_meta_result = mysql_stmt_result_metadata(stmt);
+	if (!prepare_meta_result)
+	{
+		fprintf(stderr,
+			" mysql_stmt_result_metadata(), \
+           returned no meta information\n");
+		fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
+		exit(0);
+	}
+
+	/* Get total columns in the query */
+	column_count = mysql_num_fields(prepare_meta_result);
+	fprintf(stdout,
+		" total columns in SELECT statement: %d\n",
+		column_count);
+
+	if (column_count != 4) /* validate column count */
+	{
+		fprintf(stderr, " invalid column count returned by MySQL\n");
+		exit(0);
+	}
+
+	/* Bind the result buffers for all 4 columns before fetching them */
+
+	memset(bind, 0, sizeof(bind));
+
+	/* INTEGER COLUMN */
+	bind[0].buffer_type = MYSQL_TYPE_LONG;
+	bind[0].buffer = (char*)&int_data;
+	bind[0].is_null = &is_null[0];
+	bind[0].length = &length[0];
+	bind[0].error = &error[0];
+
+	/* STRING COLUMN */
+	bind[1].buffer_type = MYSQL_TYPE_STRING;
+	bind[1].buffer = (char*)str_data;
+	bind[1].buffer_length = STRING_SIZE;
+	bind[1].is_null = &is_null[1];
+	bind[1].length = &length[1];
+	bind[1].error = &error[1];
+
+	/* SMALLINT COLUMN */
+	bind[2].buffer_type = MYSQL_TYPE_SHORT;
+	bind[2].buffer = (char*)&small_data;
+	bind[2].is_null = &is_null[2];
+	bind[2].length = &length[2];
+	bind[2].error = &error[2];
+
+	/* TIMESTAMP COLUMN */
+	bind[3].buffer_type = MYSQL_TYPE_TIMESTAMP;
+	bind[3].buffer = (char*)&ts;
+	bind[3].is_null = &is_null[3];
+	bind[3].length = &length[3];
+	bind[3].error = &error[3];
+
+	/* Bind the result buffers */
+	if (mysql_stmt_bind_result(stmt, bind))
+	{
+		fprintf(stderr, " mysql_stmt_bind_result() failed\n");
+		fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
+		exit(0);
+	}
+
+	/* Now buffer all results to client (optional step) */
+	if (mysql_stmt_store_result(stmt))
+	{
+		fprintf(stderr, " mysql_stmt_store_result() failed\n");
+		fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
+		exit(0);
+	}
+
+	/* Fetch all rows */
+	row_count = 0;
+	fprintf(stdout, "Fetching results ...\n");
+	while (!mysql_stmt_fetch(stmt))
+	{
+		row_count++;
+		fprintf(stdout, "  row %d\n", row_count);
+
+		/* column 1 */
+		fprintf(stdout, "   column1 (integer)  : ");
+		if (is_null[0])
+			fprintf(stdout, " NULL\n");
+		else
+			fprintf(stdout, " %d(%ld)\n", int_data, length[0]);
+
+		/* column 2 */
+		fprintf(stdout, "   column2 (string)   : ");
+		if (is_null[1])
+			fprintf(stdout, " NULL\n");
+		else
+			fprintf(stdout, " %s(%ld)\n", str_data, length[1]);
+
+		/* column 3 */
+		fprintf(stdout, "   column3 (smallint) : ");
+		if (is_null[2])
+			fprintf(stdout, " NULL\n");
+		else
+			fprintf(stdout, " %d(%ld)\n", small_data, length[2]);
+
+		/* column 4 */
+		fprintf(stdout, "   column4 (timestamp): ");
+		if (is_null[3])
+			fprintf(stdout, " NULL\n");
+		else
+			fprintf(stdout, " %04d-%02d-%02d %02d:%02d:%02d (%ld)\n",
+				ts.year, ts.month, ts.day,
+				ts.hour, ts.minute, ts.second,
+				length[3]);
+		fprintf(stdout, "\n");
+	}
+
+	/* Validate rows fetched */
+	fprintf(stdout, " total rows fetched: %d\n", row_count);
+	if (row_count != 2)
+	{
+		fprintf(stderr, " MySQL failed to return all rows\n");
+		exit(0);
+	}
+
+	/* Free the prepared result metadata */
+	mysql_free_result(prepare_meta_result);
+
+
+	/* Close the statement */
+	if (mysql_stmt_close(stmt))
+	{
+		/* mysql_stmt_close() invalidates stmt, so call          */
+		/* mysql_error(mysql) rather than mysql_stmt_error(stmt) */
+		fprintf(stderr, " failed while closing the statement\n");
+		fprintf(stderr, " %s\n", mysql_error(mysql));
+		exit(0);
+	}
+}