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Editor to share with you how to use the ibatis tag, I believe that most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to understand it!

When I read the ibatis document, I saw this tag, and I didn't know much about it. I didn't know the specific meaning of this tag until now, when I used the tag in my work. First, post the introduction to the tags in the document and share them together.

Tag: this attribute traverses the entire collection and repeats the contents of the element body for the elements in the List collection.

Attributes of the tag:

Components of SQL statements that can be overridden by prepend-, added in front of the statement (optional)

Element for traversal with property- type java.util.List (required)

Open- the string at the beginning of the entire traversal of the content body, used to define parentheses (optional)

Close- the string at the end of the entire traversal content body, used to define parentheses (optional)

Conjunction- A string between each traversal of content, used to define AND or OR (optional)

Iterate- traverses elements of type java.util.List (or array).

Example:

Username=#userNameList [] #

Note: when using tags, it is important to include square brackets [] after the List element name, and square brackets [] mark the object as List in case the parser simply outputs List to String.

My own understanding of the above tag is as follows:

When the sql statement is generated, the content in the tag is generated in a loop. Take the example above, and the generated sql is (username=xxx1 or username=xxx2 or username=xxx 3) instead of (username=xxx1 or xxx2 or xxx3), as shown below:

Id in

# ids [] #

. (1)

The sql statement it generates is: id in (xx1,xx2,xx3,.), and the parentheses (including parentheses) are generated by the tag.

Although the tag traverses the entire collection, the tag does not cycle through the contents of the tag like the for we use in java, but uses list or array to generate the entire runnable sql statement at one time. Just like (1) the sql it generates can't be like this: id in (xx1)

Id in (xx2), id in (xx3),

The above is all the content of this article "how to use ibatis tags". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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