Dynamic SQL of ibatis

1. Introduce

 1 <select id="getUsers"
 2 
 3 parameterClass="user"
 4 
 5 resultMap="get-user-result"> 
 6 
 7 select
 8 
 9 id,
10 
11 name,
12 
13 sex
14 
15 from t_user
16 
17 <dynamic prepend="WHERE">
18 
19    <isNotEmpty prepend="AND" property="name">
20 
21        name like #name#
22 
23    </isNotEmpty>
24 
25    <isNotEmpty prepend="AND" property="address">
26 
27        address like #address#
28 
29    </isNotEmpty>
30 
31 </dynamic>
32 
33 </select>

Copy

adopt dynamic node , You can define a dynamic WHERE Clause . this WHERE Clause may contain two statements for name and address The judgment condition of the field . Whether these two fields are added to the search depends on the query conditions provided by the user .

The semantics of this node is , If the parameter class ”name” Property is not empty （isNotEmpty, That is, a non empty string ””）, In the generated SQL Where The sentence includes the judgment condition (name like #name#), among #name# Will take the name Property value padding .

name Property corresponds to isNotEmpty node , because ibatis Will automatically determine whether to add prepend Prefix , here (name like #name#) yes WHERE The first conditional clause in clause , There is no need to AND Prefix , So automatically omit .

Decision nodes are not limited to isNotEmpty,ibatis Provides a wealth of decision definition functions . It can be divided into two categories ：

One 、 Monism

Unary decision is the decision of attribute value itself , If the attribute is NULL, Whether it is null, etc .

In the above example isNotEmpty It's a typical unary decision .

The unary decision node has ：

<isPropertyAvailable> Whether this property is provided in the parameter class

<isNotPropertyAvailable> And <isPropertyAvailable> contrary

<isNull> Whether the attribute value is NULL

<isNotNull> And <isNull> contrary

<isEmpty> If the property is Collection perhaps String, Its size whether <1,

If not the above two types , Through

String.valueOf( Property value )

Get it String After the value of type , Judge it size whether <1

<isNotEmpty> And <isEmpty> contrary .

Two 、 Binary decision

Binary decision has two decision parameters , One is the attribute name , It's the decision value , Such as

<isGreaterThan prepend=”AND” property=”age”

compareValue=”18″>

(age=#age#)

</isGreaterThan>

among ,property=”age” Property name specified ”age”,compareValue=”18” To specify

The judgment value is ”18”.

The above decision node isGreaterThan The corresponding semantics is ： If age Property is greater than

18(compareValue), It's in SQL Add (age=#age#) Conditions .

The binary decision nodes are ：

The node name Property value and compareValues The relationship between

<isEqual> equal .

<isNotEqual> Unequal .

<isGreaterThan> Greater than

<isGreaterEqual> Greater than or equal to

<isLessThan> Less than

<isLessEqual> Less than or equal to

2. The Works of Liezi

For some special symbols , If greater than >、 Less than no. < You need to write in <![CDATA[]] China can effectively , Otherwise, it will fail . 1、 dynamic SQL fragment

adopt SQL Fragments achieve code reuse

 1 <!--  Dynamic conditional paging query  --> 
 2         <sql id="sql_count"> 
 3                 select count(*) 
 4         </sql> 
 5         <sql id="sql_select"> 
 6                 select * 
 7         </sql> 
 8         <sql id="sql_where"> 
 9                 from icp 
10                 <dynamic prepend="where"> 
11                         <isNotEmpty prepend="and" property="name"> 
12                                 name like '%$name$%' 
13                         </isNotEmpty> 
14                         <isNotEmpty prepend="and" property="path"> 
15                                 path like '%path$%' 
16                         </isNotEmpty> 
17                         <isNotEmpty prepend="and" property="area_id"> 
18                                 area_id = #area_id# 
19                         </isNotEmpty> 
20                         <isNotEmpty prepend="and" property="hided"> 
21                                 hided = #hided# 
22                         </isNotEmpty> 
23                 </dynamic> 
24                 <dynamic prepend=""> 
25                         <isNotNull property="_start"> 
26                                 <isNotNull property="_size"> 
27                                         limit #_start#, #_size# 
28                                 </isNotNull> 
29                         </isNotNull> 
30                 </dynamic> 
31         </sql> 
32         <select id="findByParamsForCount" parameterClass="map" resultClass="int"> 
33                 <include refid="sql_count"/> 
34                 <include refid="sql_where"/> 
35         </select> 
36         <select id="findByParams" parameterClass="map" resultMap="icp.result_base"> 
37                 <include refid="sql_select"/> 
38                 <include refid="sql_where"/> 
39 
40         </select>

Copy

2、 Number range query

The parameter name is fabricated , Non database fields , such as _img_size_ge、_img_size_lt Field

 1 <isNotEmpty prepend="and" property="_img_size_ge"> 
 2                                 <![CDATA[ 
 3                                 img_size >= #_img_size_ge# 
 4                         ]]> 
 5                         </isNotEmpty> 
 6                         <isNotEmpty prepend="and" property="_img_size_lt"> 
 7                                 <![CDATA[ 
 8                                 img_size < #_img_size_lt# 
 9                         ]]> 
10                         </isNotEmpty> 
11 
12  

Copy

Multiple use of one parameter is also allowed

 1 <isNotEmpty prepend="and" property="_now"> 
 2                                 <![CDATA[ 
 3                                             execplantime >= #_now# 
 4                                      ]]> 
 5                         </isNotEmpty> 
 6                         <isNotEmpty prepend="and" property="_now"> 
 7                                 <![CDATA[ 
 8                                             closeplantime <= #_now# 
 9                                      ]]> 
10                         </isNotEmpty>

Copy

3、 Time range query

1 <isNotEmpty prepend="" property="_starttime"> 
2                                 <isNotEmpty prepend="and" property="_endtime"> 
3                                         <![CDATA[ 
4                                         createtime >= #_starttime# 
5                                         and createtime < #_endtime# 
6                                  ]]> 
7                                 </isNotEmpty> 
8                         </isNotEmpty> 

Copy

4、in Inquire about

1 <isNotEmpty prepend="and" property="_in_state"> 
2                                 state in ('$_in_state$') 
3                         </isNotEmpty>

Copy

5、like Inquire about

1 <isNotEmpty prepend="and" property="chnameone"> 
2                                 (chnameone like '%$chnameone$%' or spellinitial like '%$chnameone$%') 
3                         </isNotEmpty> 
4                         <isNotEmpty prepend="and" property="chnametwo"> 
5                                 chnametwo like '%$chnametwo$%' 
6                         </isNotEmpty> 

Copy

6、or Conditions

 1 <isEqual prepend="and" property="_exeable" compareValue="N"> 
 2                                 <![CDATA[ 
 3                                 (t.finished='11'    or t.failure=3) 
 4                         ]]> 
 5                         </isEqual>
 6 
 7 <isEqual prepend="and" property="_exeable" compareValue="Y"> 
 8                                 <![CDATA[ 
 9                                 t.finished in ('10','19') and t.failure<3 
10                         ]]> 
11                         </isEqual>

Copy

7、where Subquery

 1 <isNotEmpty prepend="" property="exprogramcode"> 
 2                                 <isNotEmpty prepend="" property="isRational"> 
 3                                         <isEqual prepend="and" property="isRational" compareValue="N"> 
 4                                                 code not in 
 5                                                 (select t.contentcode 
 6                                                 from cms_ccm_programcontent t 
 7                                                 where t.contenttype='MZNRLX_MA' 
 8                                                 and t.programcode = #exprogramcode#) 
 9                                         </isEqual> 
10                                 </isNotEmpty> 
11                         </isNotEmpty>
12 
13 <select id="findByProgramcode" parameterClass="string" resultMap="cms_ccm_material.result"> 
14                 select * 
15                 from cms_ccm_material 
16                 where code in 
17                 (select t.contentcode 
18                 from cms_ccm_programcontent t 
19                 where t.contenttype = 'MZNRLX_MA' 
20                 and programcode = #value#) 
21                 order by updatetime desc 
22         </select>

Copy

9、 Use of functions

 1 <!--  add to  --> 
 2         <insert id="insert" parameterClass="RuleMaster"> 
 3                 insert into rulemaster( 
 4                 name, 
 5                 createtime, 
 6                 updatetime, 
 7                 remark 
 8                 ) values ( 
 9                 #name#, 
10                 now(), 
11                 now(), 
12                 #remark# 
13                 ) 
14                 <selectKey keyProperty="id" resultClass="long"> 
15                         select LAST_INSERT_ID() 
16                 </selectKey> 
17         </insert> 
18         <!--  to update  --> 
19         <update id="update" parameterClass="RuleMaster"> 
20                 update rulemaster set 
21                 name = #name#, 
22                 updatetime = now(), 
23                 remark = #remark# 
24                 where id = #id# 
25         </update>

Copy

10、map Result set

 1 <!--  Dynamic conditional paging query  --> 
 2         <sql id="sql_count"> 
 3                 select count(a.*) 
 4         </sql> 
 5         <sql id="sql_select"> 
 6                 select a.id                vid, 
 7                 a.img             imgurl, 
 8                 a.img_s         imgfile, 
 9                 b.vfilename vfilename, 
10     b.name            name, 
11                 c.id                sid, 
12                 c.url             url, 
13                 c.filename    filename, 
14                 c.status        status 
15         </sql> 
16         <sql id="sql_where"> 
17                 From secfiles c, juji b, videoinfo a 
18                 where 
19                 a.id = b. videoid 
20                 and b.id = c.segmentid 
21                 and c.status = 0 
22                 order by a.id asc,b.id asc,c.sortnum asc 
23                 <dynamic prepend=""> 
24                         <isNotNull property="_start"> 
25                                 <isNotNull property="_size"> 
26                                         limit #_start#, #_size# 
27                                 </isNotNull> 
28                         </isNotNull> 
29                 </dynamic> 
30         </sql> 
31         <!--  Returns the total number of records not downloaded  --> 
32         <select id="getUndownFilesForCount" parameterClass="map" resultClass="int"> 
33                 <include refid="sql_count"/> 
34                 <include refid="sql_where"/> 
35         </select> 
36         <!--  Return records that have not been downloaded  --> 
37         <select id="getUndownFiles" parameterClass="map" resultClass="java.util.HashMap"> 
38                 <include refid="sql_select"/> 
39                 <include refid="sql_where"/> 
40         </select>

Copy

Publisher ： Full stack programmer stack length , Reprint please indicate the source ：https://javaforall.cn/109452.html Link to the original text ：https://javaforall.cn