MySQL NDB 叢集 8.1 手冊
MySQL NDB 叢集 8.0 手冊
NDB 叢集內部結構手冊
在執行此範例之前,請在連線至叢集的 SQL 節點上啟動 mysql 用戶端工作階段,並執行下列陳述式以建立範例所使用的資料庫和資料表。
mysql> CREATE DATABASE ndbapi_examples;
mysql> USE ndbapi_examples;
mysql> CREATE TABLE basic (
> ATTR1 INT NOT NULL PRIMARY KEY,
> ATTR2 INT NOT NULL
> ) ENGINE=NDB;
執行範例後,您可以使用 mysql 用戶端中的 SELECT * FROM basic
來檢查資料表,或執行範例讀取程式(請參閱第 2.5.1.3 節,「NDB API 基本讀取範例」)。
您也可以在檔案 storage/ndb/ndbapi-examples/ndbapi_basic/ndbapi_basic_insert.cpp
中找到此範例的原始碼。
#include <iostream>
#include <cstdlib>
#include <string>
#include <NdbApi.hpp>
class BasicInsert
{
public:
BasicInsert(const char *connectstring)
: m_connection(connectstring), m_ndb(&m_connection, "ndbapi_examples") {}
bool init();
bool do_insert(long long, long long);
private:
Ndb_cluster_connection m_connection;
Ndb m_ndb;
inline bool on_error(const struct NdbError &error,
const std::string &explanation)
{
// prints error in format:
// ERROR <NdbErrorCode>: <NdbError message>
// explanation what went wrong on higher level (in the example code)
std::cout << "ERROR "<< error.code << ": " << error.message << std::endl;
std::cout << explanation << std::endl;
return false;
}
};
int main(int argc, char **argv)
{
if (argc != 4)
{
std::cout << "Usage: "
<< "ndb_ndbapi_basic_insert <connectstring> <key: int> <value: int>"
<< std::endl;
return EXIT_FAILURE;
}
const char *connectstring = argv[1];
const long long key = std::strtoll(argv[2], nullptr, 10);
const long long value = std::strtoll(argv[3], nullptr, 10);
ndb_init();
{
BasicInsert example(connectstring);
if (!example.init()) return EXIT_FAILURE;
// Let's verify inserts
if (example.do_insert(key, value))
std::cout << "Done, check your database:\n"
<< "\t SELECT * FROM ndbapi_examples.basic;\n"
<< "\t or run the example: ndb_ndbapi_basic_read"
<< std::endl;
else return EXIT_FAILURE;
}
ndb_end(0);
return EXIT_SUCCESS;
}
bool BasicInsert::do_insert(long long key, long long value)
{
const NdbDictionary::Dictionary *dict = m_ndb.getDictionary();
const NdbDictionary::Table *table = dict->getTable("basic");
if (table == nullptr)
return on_error(dict->getNdbError(),
"Failed to access 'ndbapi_examples.basic'");
// The insert will be performed within single transaction
NdbTransaction *transaction = m_ndb.startTransaction(table);
if(transaction == nullptr)
return on_error(m_ndb.getNdbError(), "Failed to start transaction");
NdbOperation *operation = transaction->getNdbOperation(table);
if(operation == nullptr)
return on_error(transaction->getNdbError(),
"Failed to start insert operation");
operation->insertTuple();
operation->equal("ATTR1", key);
operation->setValue("ATTR2", value);
if (transaction->execute(NdbTransaction::Commit) != 0)
return on_error(transaction->getNdbError(),
"Failed to execute transaction");
m_ndb.closeTransaction(transaction);
return true;
}
bool BasicInsert::init()
{
if (m_connection.connect() != 0)
{
std::cout << "Cannot connect to cluster management server" << std::endl;
return false;
}
if (m_connection.wait_until_ready(30, 0) != 0)
{
std::cout << "Cluster was not ready within 30 secs" << std::endl;
return false;
}
if (m_ndb.init() != 0)
return on_error(m_ndb.getNdbError(), "Failed to initialize ndb object");
return true;
}