2024年1月5日发(作者：含va高的食物排名)
cout<< "--------" next()) {if (type ==NUMOFFSET) {cout<< rs -> getString(colidx) <}else if (type ==COLNAME) {cout<< rs -> getString(colname) <}//if-else} //whilecout<}//retrieve_data_and_print()static void retrieve_dbmetadata_and_print (Connection *dbcon) {if (dbcon ->isClosed()) {throwruntime_error("DatabaseMetaData FAILURE - database connection closed");}cout<< "nDatabase Metadata" dbcon_meta (dbcon -> getMetaData());DatabaseMetaData*dbcon_meta = dbcon ->getMetaData();cout<< "Database Product Name:" << dbcon_meta -> getDatabaseProductName() getDatabaseProductVersion() getUserName() << endl getDriverName() getDriverVersion() << endl isReadOnly() supportsTransactions() supportsDataManipulationTransactionsOnly() supportsBatchUpdates() supportsOuterJoins() supportsMultipleTransactions() supportsNamedParameters() supportsStatementPooling() supportsStoredProcedures() supportsUnion() << endl getMaxConnections() getMaxColumnsInTable() <
cout<< "Maximum Columns per Index:" << dbcon_meta -> getMaxColumnsInIndex() getMaxRowSize() << "bytes" rs ( dbcon_meta ->getSchemas());cout<< "nTotal number of schemas =" << rs -> rowsCount() getString("TABLE_SCHEM") <}//whilecout<< endl <}//retrieve_dbmetadata_and_print()static void retrieve_rsmetadata_and_print (ResultSet *rs) {if (rs -> rowsCount() == 0) {throwruntime_error("ResultSetMetaData FAILURE - no records in the result set");}cout<< "ResultSet Metadata" res_meta ( rs -> getMetaData() );ResultSetMetaData*res_meta = rs ->getMetaData();int numcols = res_meta ->getColumnCount();cout<< "nNumber of columns in the result set =" << numcols << endl <(20);cout<< "Column Name/Label";(20);cout<< "Column Type";(20);cout<< "Column Size" <(20);cout<< res_meta -> getColumnLabel (i+1);(20);cout<< res_meta -> getColumnTypeName (i+1);(20);cout<< res_meta -> getColumnDisplaySize (i+1) << endl <}cout<< "nColumn "" << res_meta -> getColumnLabel(1);cout<< "" belongs to the Table: "" << res_meta -> getTableName(1);cout<< "" which belongs to the Schema: "" << res_meta -> getSchemaName(1) << """ << endl <
}//retrieve_rsmetadata_and_print()int main(int argc, const char *argv[]) {Driver*driver;Connection*con;Statement*stmt;ResultSet*res;PreparedStatement*prep_stmt;Savepoint*savept;int updatecount = 0;/*initiate url, user, password and database variables*/string url(argc >= 2 ? argv[1] : DBHOST);const string user(argc >= 3 ? argv[2] : USER);const string password(argc >= 4 ?argv[3] : PASSWORD);const string database(argc >= 5 ? argv[4] : DATABASE);try{driver=get_driver_instance();/*create a database connection using the Driver*/con= driver ->connect(url, user,password);/*alternate syntax using auto_ptr to create the db connection*///auto_ptr con (driver -> connect(url, user, password));/*turn off the autocommit*/con-> setAutoCommit(0);cout<< "nDatabase connection's autocommit mode =" << con -> getAutoCommit() createStatement();cout<< "Executing the Query: "SELECT * FROM City" .." < executeQuery ("SELECT * FROM City");cout<< "Retrieving the result set .." setString (1, "London, UK");updatecount= prep_stmt ->executeUpdate();cout<< "tCreating a save point "SAVEPT1" .." setSavepoint ("SAVEPT1");cout<< "tInserting "Paris, France" into the table, City .." setString (1, "Paris, France");updatecount= prep_stmt ->executeUpdate();cout<< "tRolling back until the last save point "SAVEPT1" .." rollback (savept);con->releaseSavepoint (savept);cout<< "tCommitting outstanding updates to the database .." commit();cout<< "nQuerying the City table again .." executeQuery ("SELECT * FROM City");/*retrieve the data from the result set and display onstdout*/retrieve_data_and_print (res, COLNAME,1, string ("CityName"));
cout<< "Cleaning up the resources .." close();delete con;}catch (SQLException &e) {cout<< "ERROR: SQLException in" <<__file__>cout<< "(" << __func__<< ") on line" << __LINE__ cout<< "(" << __func__ << ") on line" << __LINE__
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