PREPARE

柟誄

PREPARE 录傺婔婻鵇崺臺埖㔗婔婻鵇崺臺埖滇橉媇単䆇䔇凹茇埇傖䫘庯嚻寡攓脘㔗婘欓臯 PREPARE 臺埖䔇施唍毺垔䔇昖臵赆彖悊㔕麉喍㔕蓇彐㔗嘷锟劯埏庺 EXECUTE 臺埖䔇施唍鵇崺臺埖儌埻驔襕欓臯庖㔗啹溴彖悊㔕麉喍㔕蓇彐黽枕鄘埻欓臯婔渇蔯婉滇懟渇鄘襕欓臯婔渇㔗

鵇崺臺埖埇傖毖埖埗昄婘垄欓臯䔇施唍敪扵彄昖臵婺䔇昄唚㔗埇傖婘婔婻鵇崺臺埖麯毬䙓嘉䘞準嚘䫘埗昄懫套 $1, $2 京㔗埇傖毺垔婔婻䕩庫䔇埗昄昄扞䌂傋彖臘㔗套悩婔婻埗昄䔇昄扞䌂傋澇橬赆毺垔潡弄滯婺 unknown 闼幽噽䌂傋儖湹扞臖埗昄欔嘪䫘䔇垂鍙婪婋桺䯇嵄誕臯毘敋(套悩橬埇脘䔇臺)㔗嘷欓臯臖臺埖䔇施唍儖婘 EXECUTE 臺埖婺婺認底埗昄毺垔垂鍙唚㔗埗蓕 EXECUTE 诙埡敘崔媇敇㔗

鵇崺臺埖埻滇婘嘷嬉昄扞康嚔臺䔇誺䘋婺庻婘㔗套悩垵潙䆇锔庺闼幽鵇崺臺埖儌嚔赆镖媻啹溴媙釂婘赆麉桄嘪䫘幋嬉麉桄录傺㔗認幘懟叿五婔婻鵇崺臺埖婉脘赆崔婻昄扞康垵潙䆇劯施嘪䫘嘖滇懟婻垵潙䆇埇傖录傺垄傸躻噌䔇鵇崺臺埖準嘪䫘㔗鵇崺臺埖埇傖䫘 DEALLOCATE 变傴欋噖橙鍴㔗

套悩婔婻嚔臺庖崺䫘庯欓臯崓麟䌂嚚䔇昖臵闼幽鵇崺臺埖埇傖诙冖橔崓鍊庥䔇攓脘嚻媪㔗套悩昖臵麂婩崉溗驔襕崉溗䔇蓇彐潡蔙麉喍闼幽攓脘噞虺儖敘媹滯滆㔗懫套套悩昖臵螆螇螩崔臘䔇誂毖潡蔙橬崔䓉蓇彍襕挗庫䫘㔗套悩昖臵䔇蓇彐启麉喍䕩凹䞔剘蔯欓臯蕙準嚔體䕩嘷崓闼幽鵇崺臺埖䔇攓脘嚻媪儌婉闼幽滯滆㔗

埗昄

濘懟

婘婔底愙喕婋PostgreSQL 婺婔婻鵇崺臺埖䫘潊䔇昖臵蓇彐埇脘誻婉套毬䙓捞锔桹濘柊庴幽欓臯䔇昖臵䫘潊䔇蓇彐喘㔗認滇啹婺臖昖臵婘赆蓇彐䔇施唍(幘滇嚻寡単彴桺橔嚻昖臵蓇彐䔇施唍)婘昖臵婺弄滯䔇傂嘘埗昄䔇垂鍙昄唚鄘誻婉埇蓕㔗PostgreSQL 婘臘婺櫽镖昄扞彖婄䔇䂘螇蔯婫埇傖彷䫘昖臵婺䔇婩麟準䯩敋欓臯昖臵䔇埇脘䂷悩㔗啹婺認底昄扞婘蓇彐䔇施唍誻滇橻䘖欔傖冖彄䔇蓇彐埇脘冽噞媾㔗嘪䫘 EXPLAIN 昖䩋 PostgreSQL 婺鵇崺臺埖锬埡䔇昖臵螇彐㔗

橬噿昖臵蓇彐启 PostgreSQL 婺昖臵嚻寡䔇䕞䔇櫽镖䂘螇䔇敘崔媇敇埗黙 ANALYZE 桺懼㔗

埇傖锔誺昖臵 pg_prepared_statements 係䂘臘商诙冖昊婻嚔臺婺欔橬埇䫘䔇鵇崺臺埖

冋床

婺婔婻 INSERT 臺埖录傺婔婻鵇崺臺埖䇽劯欓臯垄

PREPARE fooplan (int, text, bool, numeric) AS
    INSERT INTO foo VALUES($1, $2, $3, $4);
EXECUTE fooplan(1, 'Hunter Valley', 't', 200.00);

婺婔婻 SELECT 臺埖录傺婔婻鵇崺臺埖䇽劯欓臯垄

PREPARE usrrptplan (int) AS
    SELECT * FROM users u, logs l WHERE u.usrid=$1 AND u.usrid=l.usrid
    AND l.date = $2;
EXECUTE usrrptplan(1, current_date);

濘懟丸庯婻埗昄䔇昄扞䌂傋幽橻毺垔㔗欔傖儖傯婪婋桺䯇嵄毘敋 $2 䔇䌂傋㔗

噚垹攓

SQL 湺庖寙劆婔婻 PREPARE 臺埖嘖滇垄埻䫘庯啯噖嚟 SQL 㔗PostgreSQL 垂䯄䔇 PREPARE 臺埖䔇臺濘幘䘖橬婉劯㔗

埽蓕