DatabaseDatastore Объект и MySQLВ этом примере показано, как использовать databaseDatastore функция для создания DatabaseDatastore объект для доступа к наборам данных, хранящихся в базе данных MySQL ®, с помощью собственного интерфейса MySQL. После создания DatabaseDatastore можно предворительно просматривать данные, читать данные в фрагменты и читать каждую запись в наборе данных.
Чтобы анализировать большие данные, можно запустить алгоритмы на больших наборах данных с помощью длинный массив. Также можно написать алгоритм MapReduce, который задает куски и сокращение данных.
Этот пример использует предварительно сконфигурированный источник данных MySQL для создания подключения к базе данных. Для получения дополнительной информации смотрите databaseConnectionOptions функция.
DatabaseDatastore ОбъектСоздайте подключение базы данных собственного интерфейса MySQL к базе данных MySQL с помощью имени источника данных, имени пользователя и пароля.
datasource = "MySQLDataSource"; username = "root"; password = "matlab"; conn = mysql(datasource,username,password);
Создайте DatabaseDatastore объект с использованием подключения к базе данных и SQL-запроса. Этот запрос извлекает все данные из airlinesmall таблица.
sqlquery = "select * from airlinesmall";
dbds = databaseDatastore(conn,sqlquery); DatabaseDatastore ОбъектПредварительный просмотр первых восьми записей в наборе данных, возвращенных при выполнении SQL-запроса.
preview(dbds)
ans=8×29 table
Year Month DayofMonth DayOfWeek DepTime CRSDepTime ArrTime CRSArrTime UniqueCarrier FlightNum TailNum ActualElapsedTime CRSElapsedTime AirTime ArrDelay DepDelay Origin Dest Distance TaxiIn TaxiOut Cancelled CancellationCode Diverted CarrierDelay WeatherDelay NASDelay SecurityDelay LateAircraftDelay
____ _____ __________ _________ _______ __________ _______ __________ _____________ _________ ________ _________________ ______________ _______ ________ ________ ______ _____ ________ ______ _______ _________ ________________ ________ ____________ ____________ ________ _____________ _________________
1990 9 11 2 1810 1812 1939 1930 "AA" 1426 "NA" 89 78 "NA" 9 -2 "RST" "ORD" 268 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1990 10 27 6 1353 1355 1634 1640 "US" 112 "NA" 161 165 "NA" -6 -2 "TPA" "SYR" 1104 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1990 10 23 2 1057 1055 1205 1155 "US" 1621 "NA" 68 60 "NA" 10 2 "ROC" "EWR" 246 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1990 10 8 1 1515 1440 1609 1535 "NW" 749 "NA" 54 55 "NA" 34 35 "MSP" "FSD" 197 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1990 10 19 5 1130 1120 1203 1154 "UA" 369 "NA" 93 94 "NA" 9 10 "BUF" "ORD" 473 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1990 10 12 5 1755 1733 1858 1820 "DL" 590 "NA" 63 47 "NA" 38 22 "BOS" "BGR" 201 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
2001 11 22 4 1345 1355 1530 1549 "MQ" 4982 "#NAME?" 105 114 "90" -19 -10 "JAX" "MIA" 334 "8" "7" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
2001 11 26 1 2105 2110 2209 2237 "AA" 1947 "N3BäA1" 64 87 "47" -28 -5 "SFO" "LAX" 337 "6" "11" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
DatabaseDatastore ОбъектПрочитайте первые 10 записей.
dbds.ReadSize = 10; read(dbds)
ans=10×29 table
Year Month DayofMonth DayOfWeek DepTime CRSDepTime ArrTime CRSArrTime UniqueCarrier FlightNum TailNum ActualElapsedTime CRSElapsedTime AirTime ArrDelay DepDelay Origin Dest Distance TaxiIn TaxiOut Cancelled CancellationCode Diverted CarrierDelay WeatherDelay NASDelay SecurityDelay LateAircraftDelay
____ _____ __________ _________ _______ __________ _______ __________ _____________ _________ ________ _________________ ______________ _______ ________ ________ ______ _____ ________ ______ _______ _________ ________________ ________ ____________ ____________ ________ _____________ _________________
1990 9 11 2 1810 1812 1939 1930 "AA" 1426 "NA" 89 78 "NA" 9 -2 "RST" "ORD" 268 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1990 10 27 6 1353 1355 1634 1640 "US" 112 "NA" 161 165 "NA" -6 -2 "TPA" "SYR" 1104 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1990 10 23 2 1057 1055 1205 1155 "US" 1621 "NA" 68 60 "NA" 10 2 "ROC" "EWR" 246 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1990 10 8 1 1515 1440 1609 1535 "NW" 749 "NA" 54 55 "NA" 34 35 "MSP" "FSD" 197 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1990 10 19 5 1130 1120 1203 1154 "UA" 369 "NA" 93 94 "NA" 9 10 "BUF" "ORD" 473 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1990 10 12 5 1755 1733 1858 1820 "DL" 590 "NA" 63 47 "NA" 38 22 "BOS" "BGR" 201 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
2001 11 22 4 1345 1355 1530 1549 "MQ" 4982 "#NAME?" 105 114 "90" -19 -10 "JAX" "MIA" 334 "8" "7" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
2001 11 26 1 2105 2110 2209 2237 "AA" 1947 "N3BäA1" 64 87 "47" -28 -5 "SFO" "LAX" 337 "6" "11" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
2001 11 18 7 1407 1415 1442 1457 "DL" 628 "N521D1" 35 42 "22" -15 -8 "OKC" "TUL" 111 "3" "10" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
2001 12 23 7 1327 1310 1530 1530 "WN" 658 "N789@@" 63 80 "48" 0 17 "SNA" "PHX" 338 "5" "10" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
Чтение DatabaseDatastore объект еще два раза при помощи счетчика n. Считывайте по 10 записей за раз.
n = 0; while(hasdata(dbds) && n~=2) read(dbds) n = n+1; end
ans=10×29 table
Year Month DayofMonth DayOfWeek DepTime CRSDepTime ArrTime CRSArrTime UniqueCarrier FlightNum TailNum ActualElapsedTime CRSElapsedTime AirTime ArrDelay DepDelay Origin Dest Distance TaxiIn TaxiOut Cancelled CancellationCode Diverted CarrierDelay WeatherDelay NASDelay SecurityDelay LateAircraftDelay
____ _____ __________ _________ _______ __________ _______ __________ _____________ _________ ________ _________________ ______________ _______ ________ ________ ______ _____ ________ ______ _______ _________ ________________ ________ ____________ ____________ ________ _____________ _________________
2001 12 8 6 1402 1410 1642 1626 "NW" 809 "N324N2" 220 196 "199" 16 -8 "BOS" "MEM" 1139 "4" "17" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
2001 12 22 6 1707 1715 1823 1821 "UA" 725 "N361ä1" 136 126 "104" 2 -8 "RIC" "ORD" 642 "20" "12" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
2001 12 9 7 656 650 824 823 "DL" 1224 "N37438" 88 93 "73" 1 6 "ATL" "BWI" 576 "4" "11" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
2002 6 19 3 632 640 748 756 "NW" 126 "N773NC" 76 76 "58" -8 -8 "BIS" "MSP" 386 "9" "9" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
2002 6 10 1 927 930 1031 1031 "UA" 501 "N304UA" 124 121 "101" 0 -3 "DFW" "DEN" 641 "5" "18" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
2002 6 15 6 1120 1115 1401 1413 "DL" 406 "N1402A" 161 178 "132" -12 5 "FLL" "LGA" 1076 "7" "22" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
2002 6 8 6 1557 1600 1703 1711 "HP" 660 "N334AW" 66 71 "52" -8 -3 "PHX" "SNA" 338 "4" "10" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
2002 6 26 3 2026 1840 47 2257 "AA" 636 "N420AA" 141 137 "115" 110 106 "PHX" "DFW" 868 "6" "20" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
2002 6 5 3 2032 2031 2233 2248 "AA" 3163 "N4WFAA" 241 257 "220" -15 1 "STL" "SMF" 1679 "8" "13" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
2002 7 25 4 1032 1035 1853 1852 "US" 180 "N174UW" 321 317 "289" 1 -3 "SEA" "PHL" 2378 "9" "23" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
ans=10×29 table
Year Month DayofMonth DayOfWeek DepTime CRSDepTime ArrTime CRSArrTime UniqueCarrier FlightNum TailNum ActualElapsedTime CRSElapsedTime AirTime ArrDelay DepDelay Origin Dest Distance TaxiIn TaxiOut Cancelled CancellationCode Diverted CarrierDelay WeatherDelay NASDelay SecurityDelay LateAircraftDelay
____ _____ __________ _________ _______ __________ _______ __________ _____________ _________ _______ _________________ ______________ _______ ________ ________ ______ _____ ________ ______ _______ _________ ________________ ________ ____________ ____________ ________ _____________ _________________
1987 10 30 5 1329 1329 1434 1436 "US" 683 "NA" 65 67 "NA" -2 0 "LGA" "BUF" 292 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1987 11 7 6 1316 1315 1713 1647 "TW" 810 "NA" 177 152 "NA" 26 1 "STL" "BOS" 1046 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1987 11 28 6 815 815 1015 1015 "WN" 441 "NA" 120 120 "NA" 0 0 "BNA" "HOU" 670 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1987 11 2 1 700 700 800 800 "NW" 790 "NA" 60 60 "NA" 0 0 "BTR" "MEM" 319 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1987 11 14 6 840 840 1127 1120 "CO" 733 "NA" 167 160 "NA" 7 0 "EWR" "MCO" 938 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1987 11 1 7 1625 1625 1823 1758 "DL" 957 "NA" 118 93 "NA" 25 0 "EWR" "CVG" 569 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1987 11 26 4 1314 1315 1538 1542 "AA" 398 "NA" 84 87 "NA" -4 -1 "BNA" "RDU" 443 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1992 7 18 6 1538 1540 1703 1720 "NW" 199 "NA" 145 160 "NA" -17 -2 "DCA" "MSP" 931 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1992 7 19 7 932 932 1130 1052 "AA" 1433 "NA" 118 80 "NA" 38 0 "DFW" "HRL" 461 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1992 8 4 2 NaN 1815 NaN 1940 "US" 127 "NA" NaN 85 "NA" NaN NaN "EWR" "PIT" 319 "NA" "NA" 1 "NA" 0 "NA" "NA" "NA" "NA" "NA"
DatabaseDatastore ОбъектСбросьте DatabaseDatastore объект в его исходном состоянии, где из него не были считаны данные. Сброс позволяет вам перечитать с того же DatabaseDatastore объект.
reset(dbds)
DatabaseDatastore ОбъектЧтение каждой записи в DatabaseDatastore объект с шагами 50 000 записей за раз.
dbds.ReadSize = 50000; data = readall(dbds);
Отображение первых трех записей полного набора данных.
head(data,3)
ans=3×29 table
Year Month DayofMonth DayOfWeek DepTime CRSDepTime ArrTime CRSArrTime UniqueCarrier FlightNum TailNum ActualElapsedTime CRSElapsedTime AirTime ArrDelay DepDelay Origin Dest Distance TaxiIn TaxiOut Cancelled CancellationCode Diverted CarrierDelay WeatherDelay NASDelay SecurityDelay LateAircraftDelay
____ _____ __________ _________ _______ __________ _______ __________ _____________ _________ _______ _________________ ______________ _______ ________ ________ ______ _____ ________ ______ _______ _________ ________________ ________ ____________ ____________ ________ _____________ _________________
1990 9 11 2 1810 1812 1939 1930 "AA" 1426 "NA" 89 78 "NA" 9 -2 "RST" "ORD" 268 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1990 10 27 6 1353 1355 1634 1640 "US" 112 "NA" 161 165 "NA" -6 -2 "TPA" "SYR" 1104 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
1990 10 23 2 1057 1055 1205 1155 "US" 1621 "NA" 68 60 "NA" 10 2 "ROC" "EWR" 246 "NA" "NA" 0 "NA" 0 "NA" "NA" "NA" "NA" "NA"
DatabaseDatastore Подключение объекта и базы данныхclose(dbds)
close | databaseDatastore | hasdata | mysql | preview | read | readall