Final summary of addition, deletion, modification and query - 2.2 (knowledge points in mapper.xml)

1、 Dynamic values / Do not take a fixed value

 #{key}     example ：id = #{id}、name = #{name}……

2、xml Escape character

    > use > Instead of
    < use &lt; Instead of
    & use &amp; Instead of
     Universal escape character  <![CDATA[ Escape content , There are >、< And so on , Will the whole sql Statement put here  ]]>

3、 ... and 、Sql label —— Example ： Add, delete, modify and check the final summary —1（ Additions and deletions ）→ Fuzzy query

Sql Repeated data often appears in statements . If you write your own handwriting every time you repeat . The efficiency of development is low ;
Sql Tags can save code
shortcoming : Readability has deteriorated , It doesn't look intuitive If it is an association operation Depending on the situation
    <!--Sql label : Draw out the public Sql sentence -->
    <sql id="tableColumn">
        id,name,age,sex
    </sql>
    
    <select id="findUserByLike" resultType="User">
        /*SELECT id,name,age,sex FROM demo_user WHERE NAME LIKE "%"#{name}"%" Just use the following line instead */
        SELECT <include refid="tableColumn"/> FROM demo_user WHERE NAME LIKE "%"#{name}"%"
    </select> <!-- among refid It means to quote -->