軟工課程part第三章對象關(guān)系數(shù)據(jù)庫

createtable select=‘Joe’(j.long–r.long)2+(j.lat–r.lat)2<-createtablesetinterest=rate(date_sold–createcreatefunctiondistance(point,point)returnfloatasexternalnamelanguage方法：用SQL或第三代語言編寫函數(shù)，到系統(tǒng)用戶定義的函數(shù)可以在SQL查詢的selectwhere 創(chuàng)建新的數(shù)據(jù)類型point，和函數(shù)distancecreatetable select=‘Joe’distance(j.location,r.location)< 例createopaquetypeinput=mytypeInput, createtype descriptionvarchar(20));createtype createtypeemployee_t( startdate addressvarchar(30), zipcode組合（記錄） createtype startdatedate, 例組合類型用于表的定義：createtableempoftype例2查找有1985selectdnamefromdept例2查找有1985selectdnamefromdeptselectfromdept.autoswhereyear=1985dep例3fromdeptwheredname=‘shoes’例4selectfromwheredname=‘shoes’例1創(chuàng)建一個函數(shù)，返回 createfunctiontransport_autosreturnssetof(auto_t)asfromdeptwheredname=‘transportation’depcreatetype manager_refref(employee_t), workerssetof(ref(employee_t)));createtabledeptoftypenameyear5........................ 例5將鞋部經(jīng)理改為Markupdatedept(selectref(emp)fromempwherename=‘Mark’)wheredname=‘shoes’的，基本類型的唯一途徑是檢索它，或執(zhí)行.1 date);createtypeemployee_t( startdatedate, _tcreatetype _t合、。動態(tài)、客戶端和服務(wù)器端啟動、安全性、回insertable3.33.3ORDB例createtype . )undertypex3.3ORDB特性三：繼承3.3.1數(shù)據(jù)繼承3.3.1數(shù)據(jù)繼承例createtypestudent_emp_t(percent 例createtable _t;createtableempofemployee_t understudent,emp;3.3.1數(shù)據(jù)繼承3.3.1數(shù)據(jù)繼承fromempwheresalary=10000electnamewheresalary=10000

代student_emp表中3.3.1數(shù)據(jù)繼承3.3.1數(shù)據(jù)繼承 startdateds繼承層次中表的：有多種不同的方法，各自對不同的查詢有性能 3.3.1數(shù)據(jù)繼承selectname P個元 selectname, 3.3.13.3.1數(shù)據(jù)繼承共同的屬性都存放在祖先表中，后代表只特有的 ;select selectname,fromemp .23.3.2函數(shù)繼承createfunctionoverpaid(employee_t)returnsbooleanasreturn$1.salary>(selectsalaryfromwherename=‘Joe’)fromempewhereoverpaid(e)3.3.2函數(shù)繼承3.3.2函數(shù)繼承returnsbooleanasreturn$1.salary>(selectfromwherename=‘Bill’)3.3.2函數(shù)繼承fromempewhereoverpaid(e)3.3.23.3.2函數(shù)繼承 例3.43.4ORDBORDBMS監(jiān)視的發(fā)生，執(zhí)行相應(yīng)的動作，從而實現(xiàn)多四類主要的規(guī)則：更新–更則查詢–更則更新–查詢規(guī)則查詢–3.4.1 createrulenew_update_updateasonupdateto=doupdateempsetsalary=wherename=‘Jane’ 3.4.1規(guī)則示例3.4.1規(guī)則示例createrulequery_queryasonselecttowherecurrent.salary>=10000doinsteadreturnrand_salary( 3.4.1規(guī)則示例 createrulequery_updateas=doinsertintoauditvalues(current.salary,user,current_timestamp);3.4.1規(guī)則示例(mechanism=createruleupdate_queryas=doalertmy-3.4.13.4.1規(guī)則示例createrulequery_queryas=dofromempwherename= 3.4.1規(guī)則示例例5查詢-查詢規(guī)則又例createviewmark_empselectname,salaryfromempwheresalary<grantselectonviewmark_emptoselectname.salaryfrommark_empwherename=‘Emma’; 例createrulestrange_1onupdatetoemp.salarywheredoupdateempsetwherecreaterulestrange_2=‘Mike’doupdateempsetsalary=2*new.salarywhere 例createrulebad_1asonupdatetoemp.salarywhere=‘Mikedoupdateempsetsalary=2*new.salarywherecreaterulebad_2=‘Jane’doupdateempsetsalary=2*new.salarywherename=一般地，規(guī)則的動作與觸發(fā)規(guī)則的處于同一個事createruleupdate_updateasonupdateto=doupdateemps