1# #Example Example =New# #Example (); 2Example.setorderbyclause ("Field name ASC");//in ascending order, DESC is in descending order. 3Example.setdistinct (false)//Remove Duplicates, Boolean, True to select records that are not duplicates. 4Criteria =NewExample (). Createcriteria (); 5IsNULL; is notNULL; 6 equal to (value); n equal to (value); 7 GreaterThan (value); Greaterthanorequalto (value); 8 LessThan (value); Lessthanorequalto (value); 9 In (Item,item,item,...); Not in (Item,item,item,...); TenLike ("%" +value+ "%") and not-like ("%" +value+ "%"); One between (value1,value2); not between (Value1,value2) A - - the example functions for mapper in MyBatis: - intCountbyexample (userexample example) Thorws SQLException: Count by condition. - intDeletebyprimarykey (Integer ID) thorws SQLException: Delete by primary key. - intDeletebyexample (userexample example) Thorws SQLException: Delete by condition. +string/Integer Insert (User record) Thorws SQLException: Insert (return value is ID value) - User Selectbyprimarykey (Integer ID) thorws SQLException: Queries by primary key. +List<?>Selectbyexample (userexample example) THORWS SQLException: query by Condition AList<?>Selectbyexamplewithblogs (userexample example) Thorws SQLException: Press at - conditional queries (including BLOB fields). Only if the field type in the data table is binary is it generated. - intUpdatebyprimarykey (User record) Thorws SQLException: Update by primary key - intupdatebyprimarykeyselective (User record) Thorws SQLException: Update by primary key - - a field with a value other than null in intupdatebyexample (User record, userexample example) Thorws SQLException: - to Update by Condition + intupdatebyexampleselective (User record, userexample example) Thorws - the SQLException: Updating a field with a value that is not NULL by condition * $ The example functions of Mapper in MyBatis are detailed:Panax Notoginseng ①selectbyprimarykey () - theUser user = # #Mapper. Selectbyprimarykey (100); Equivalent to select *From user where + AID = 100 the + ②selectbyexample () and Selectbyexamplewithblogs () - $userexample example =Newuserexample (); $Criteria =Example.createcriteria (); -Criteria.andusernameequalto ("Joe"); - Criteria.andusernameisnull (); theExample.setorderbyclause ("Username asc,email desc"); -List<?>list =# #Mapper. Selectbyexample (example); WuyiEquivalent to: SELECT * from user where username = ' Joe ' and username areNULLOrder the - by username Asc,email desc Wu - Note: The ibator generated file Userexample.java contains a static internal class Criteria, About $ There are a number of methods in the criteria, primarily defining the query criteria after the SQL statement where. - - ③insert () - AUser User =NewUser (); +User.setid (101); theUser.setusername ("Test"); -User.setpassword ("123") $User.setemail ("[Email protected]"); the # #Mapper. Insert (user); the equivalent to: INSERT INTO user (Id,username,password,email) values the the(101, ' Test ', ' 123 ', ' [email protected] '); - in ④updatebyprimarykey () and updatebyprimarykeyselective () the theUser User =NewUser (); AboutUser.setid (101); theUser.setusername ("Joe"); theUser.setpassword ("Joe"); theUser.setemail ("[Email protected]"); + # #Mapper. Updatebyprimarykey (user); -Equivalent: Update user set username= ' Joe ', password= ' Joe ', email= ' [email protected] ' the Bayiwhere id=101 the theUser User =NewUser (); -User.setid (101); -User.setpassword ("Joe"); the # #Mapper. updatebyprimarykeyselective (user); theEquivalent: Update user set password= ' Joe ' where id=101 the the ⑤updatebyexample () and updatebyexampleselective () - theuserexample example =Newuserexample (); theCriteria =Example.createcriteria (); theCriteria.andusernameequalto ("Joe"); 94User User =NewUser (); theUser.setpassword ("123"); the # #Mapper. updatebyprimarykeyselective (User,example); theEquivalent: Update user set password= ' 123 ' where username= ' Joe '98 About ⑥deletebyprimarykey () - 101# #Mapper. Deletebyprimarykey (101); Equivalent to: Delete from user where id=101102 103 ⑦deletebyexample ()104 theuserexample example =Newuserexample (); 106Criteria =Example.createcriteria (); 107Criteria.andusernameequalto ("Joe"); 108 # #Mapper. Deletebyexample (example); 109Equivalent to: Delete from user where username= ' Joe ' the 111 ⑧countbyexample () the 113userexample example =Newuserexample (); theCriteria =Example.createcriteria (); theCriteria.andusernameequalto ("Joe"); the intCount =# #Mapper. Countbyexample (example); 117Equivalent to: SELECT COUNT (*) from user where username= ' Joe '
Mapper interface files in MyBatis and instance functions of the example class and detailed