MyBatis Common Operational Database knowledge

• MyBatis generating UUID         

<InsertId="Insert"ParameterType="Custom attribute class name"><Selectkey Keyproperty=The UserId//Your primary key property name "Resulttype="String"Order="Before">Select Replace(UUID (),'-',"') fromDual//copy as is</Selectkey>Insert  intoSys_user (user_id,user_name, Login_name, user_pwd)Values(#{userid,jdbctype=VARCHAR}, #{username,jdbctype=VARCHAR}, #{loginname,jdbctype=VARCHAR}, #{userpwd,jdbctype=VARCHAR})</Insert>

• Select

<InsertId="Addbean" ParameterType="Com.test.bean.ScenicPunish">       <!--generate UUID --      <Selectkey Keyproperty="PUNISH_ID" Resulttype="Java.lang.String"Order="Before">        Select Replace(UUID (),'-',"') fromDual</Selectkey>      Insert  intot_scenic_punish (punish_id,punish_prov,punish_city,punish_country,punish_scenic,punish_org, Punish_type, Punish_date,punish_title,punish_content,punish_url)Values(#{punish_id},#{punish_prov},#{punish_city},#{punish_country},#{punish_scenic},#{punish_org},#{punish_type },#{punish_date},#{punish_title},#{punish_content},#{punish_url})</Insert>

SELECT statement Property configuration details:

Properties	Description	Take value	default
Id	A unique identifier in this mode, which can be referenced by other statements
ParameterType	The full class name or alias of the argument passed to this statement
Resulttype	Statement returns the whole class name or alias of a value type. Note that if it is a collection, it is filled with the entire class name or alias of the item in the collection, not the class name of the collection itself. (Resulttype and Resultmap cannot be used)
Resultmap	The external resultmap name of the reference. Result set mapping is the most powerful feature in MyBatis. Many complex mappings can be easily resolved. (Resulttype and Resultmap cannot be used)
Flushcache	If set to True, the cache will be emptied every time the statement is called. The SELECT statement is set to False by default	True/false	False
UseCache	If set to true, the result set of the statement is cached. The SELECT statement is set to False by default	True/false	False
Timeout	Sets the maximum time that a drive waits for a response before throwing an exception, with no value set by default and determined by the drive itself	Positive integers	Not set
Fetchsize	After setting a value, the drive returns after the number of result sets reaches this value, default is no value, determined by the drive itself	Positive integers	Drive decision
StatementType	Statement,preparedstatement,callablestatement. Pre-prepared statements, callable statements	STATEMENT, PREPARED, callable	PREPARED
ResultsetType	Forward_only, Scroll_sensitive, scroll_insensitive only forward, scrolling sensitive, case-insensitive scrolling	Forward_only, Scroll_sensitive, scroll_insensitive	Drive decision

Insert can use the automatically generated primary key policy supported by the database, set usegeneratedkeys= "true", and then set the Keyproperty to the corresponding column, it is done. For example, the studententity above uses auto-generated to generate a primary key for the ID column.
You can also define automatic Updates in the database.
or update the ID value with the UUID


<!--insert Student Auto PRIMARY KEY--<insert id=  "Insertstudentautokey" parametertype=  "studententity" > <selectKey keyproperty= "StudentID" resultType = "String" order= "BEFORE" > Select Nextval (' Student ') </selectkey> INSERT into Student_ TBL (student_id, Student_name, Student_sex, Student_birthday, class_id) VALUES (#{studentid}, #{studentname}, #{ Studentsex}, #{studentbirthday}, #{classentity.classid}) </ Insert> 
 
 
             

• Insert

<insert id="insertstudent" parametertype="studententity" Usegeneratedkeys ="true" keyproperty= "studentid" >

Id	A unique identifier in this mode, which can be referenced by other statements
ParameterType	The full class name or alias of the argument passed to this statement
Flushcache	If set to True, the cache will be emptied every time the statement is called. The SELECT statement is set to False by default	True/false	False
UseCache	If set to true, the result set of the statement is cached. The SELECT statement is set to False by default	True/false	False
Timeout	Sets the maximum time that a drive waits for a response before throwing an exception, with no value set by default and determined by the drive itself	Positive integers	Not set
Fetchsize	After setting a value, the drive returns after the number of result sets reaches this value, default is no value, determined by the drive itself	Positive integers	Drive decision
StatementType	Statement, PreparedStatement, CallableStatement. Pre-prepared statements, callable statements	STATEMENT, PREPARED, callable	PREPARED
Usegeneratedkeys	Tell MyBatis to use the JDBC Getgeneratedkeys method to get the primary key generated by the database itself (MySQL, SQL Server, and other relational databases will have automatically generated fields). Default: False	True/false	False
Keyproperty	Identifies a value returned by a key that will be set into Getgeneratedkeys by MyBatis, or a selectkey child element for the INSERT statement.

Selectkey Statement Property configuration details:

MyBatis Common Operational Database knowledge