濡備綍瑙ｅ喅Hibernate 鐨凬+1闂??
銆?span style="">闂??銆?/span>浠?箞鏃跺?浼氶亣鍒癗+1鐨勯棶棰橈紵
銆?/span>澶囨敞銆?/span>聽Hibernate榛樿?鎶撳彇絳栫暐鏄痜etch="select"錛屼笉鏄痜etch="join",杩欓兘鏄?負浜嗗歡杩熷姞杞藉?鍑嗗?鐨勩?
銆?/span>鍑虹幇鎯呭喌銆?/span>
聽 聽聽 聽聽 聽1錛変竴瀵瑰?(one-to-many) 錛屽湪1鐨勮繖鏂癸紝閫氳繃1鏉?ql鏌ユ壘寰楀埌浜?涓??璞★紝鐢變簬鍏寵仈鐨勫瓨鍦?錛岄偅涔堝張闇??灝嗚繖涓??璞″叧鑱旂殑闆嗗悎鍙栧嚭錛屾墍浠ュ悎闆嗘暟閲忔槸n杩樿?鍙戝嚭n鏉?ql錛屼簬鏄?湰鏉ョ殑1鏉?ql鏌ヨ?鍙樻垚浜喡?聽 1 +n鏉?銆?/span>
聽 聽聽 聽聽 聽2錛夊?瀵逛竴<many-to-one>聽聽錛屽湪澶氱殑杩欐柟錛岄?杩?鏉?ql鏌ヨ?寰楀埌浜唍涓??璞★紝鐢變簬鍏寵仈鐨勫瓨鍦?涔熶細灝嗚繖n涓??璞″?搴旂殑1 鏂圭殑瀵硅薄鍙栧嚭錛?浜庢槸鏈?潵鐨?鏉?ql鏌ヨ?鍙樻垚浜? +n鏉?銆?/span>
聽
聽 聽聽 聽聽 聽3錛塱terator 鏌ヨ?鏃?涓?畾鍏堝幓緙撳瓨涓?壘錛?鏉?ql鏌ラ泦鍚?鍙?煡鍑篒D錛夛紝鍦ㄦ病鍛戒腑鏃訛紝浼氬啀鎸塈D鍒闆簱涓??涓?煡鎵撅紝 浜х敓1+n鏉?QL銆?/span>
聽
銆?/span>瑙ｅ喅鍔炴硶銆?/span>
聽 聽聽聽聽 聽聽聽1錛塴azy=true錛?hibernate3寮??宸茬粡榛樿?鏄痩azy=true浜嗭紱lazy=true鏃朵笉浼氱珛鍒繪煡璇㈠叧鑱斿?璞★紝鍙?湁褰撻渶瑕佸叧鑱斿?璞★紙璁塊棶鍏跺睘鎬э紝闈瀒d瀛楁?錛夋椂鎵嶄細鍙戠敓鏌ヨ?鍔ㄤ綔銆?/span>
聽
聽 聽聽 聽聽 聽 2錛変嶠鐢ㄤ簩綰х紦瀛橈紝 浜岀駭緙撳瓨鐨勫簲鐢ㄥ皢涓嶆?1+N 闂??錛屽洜涓哄嵆浣跨?涓??鏌ヨ?寰堟參錛堟湭鍛戒腑錛夛紝浠ュ悗鏌ヨ?鐩存帴緙撳瓨鍛戒腑涔熸槸寰堝揩鐨勩?鍒氬ソ鍙堝埄鐢ㄤ簡1+N 銆?/span>
聽
聽 聽聽 聽聽 聽 3 ) 褰撶劧浣犱篃鍙?互璁懼畾fetch="join"錛屼竴嬈″叧鑱旇〃鍏ㄦ煡鍑烘潵錛屼絾澶卞幓浜嗗歡杩熷姞杞界殑鐗規?銆?/span>
聽