During the process of project development, differences in programming styles among team members and the flexibility of SQL database operation statements have increasingly added to the operational and maintenance difficulties for the project team.
For example:
To retrieve all data from the `user` table, some people might write it as "SELECT * FROM user", while others might write it as "SELECT ALL FROM user". Although there would be no errors during execution, this inconsistency can create a poor impression when others are reading the code.
If there are many such programmatic differences within a project, various coding styles will emerge during development. This can lead to significant frustration and even cursing at those who originally wrote the code during the maintenance phase (well, at least I wouldn't hesitate to scold them).
To provide examples throughout this article, let's create the following tables in the database:
**TBL_USER**
- USERID: BIGINT
- USERNAME: VARCHAR(20)
- PASSWORD: VARCHAR(20)
- CREATETIME: DATE
**TBL_USER_INFO**
- USERID: BIGINT
- EMAIL: VARCHAR(64)
- MOBILE: VARCHAR(13)
---
### **Part 1: Analysis**
#### A) Analyze SELECT Statements
Using XML to encapsulate database operation statements becomes the first step toward standardizing project operations. In this step, we will use a few examples to gradually achieve the purpose of encapsulation.
For instance, consider the statement "SELECT USERNAME, PASSWORD FROM TBL_USER". When analyzing this into an XML file, there are various ways to express it. We'll use the following format:
**Analysis 1:**
```xml
1
2
3
4
5
6
```
In the first line, the node name is `dbtrans`:
- The `name` attribute is the transaction name, here "selectUser".
- The `table` attribute is the table being queried, here "TBL_USER".
- The `method` attribute specifies the database operation method, here "select".
- The child node `` indicates that data is being read from the database.
- The `` child node represents the database fields being read, where:
- The `name` attribute is the field name.
- The `type` attribute is the field type, which can be useful in subsequent programs.
For the statement "SELECT USERNAME, PASSWORD FROM TBL_USER WHERE USERID=123", based on the above analysis, the corresponding XML would be:
**Analysis 2:**
```xml
1
2
3
4
5
6
7
8
9
```
If a `LIKE` operation is used, line 3 could be written as:
```xml
```
For the statement "SELECT USERNAME, PASSWORD FROM TBL_USER ORDER BY USERNAME DESC", the XML analysis would be:
**Analysis 3:**
```xml
1
2
3
4
5
6
6
```
This type of statement analysis can cover most common database SELECT operations. However, there may still be unforeseen database operations, such as:
"SELECT USERNAME, PASSWORD FROM TBL_USER WHERE CREATETIME > '2003-7-16' AND CREATETIME ` section. In this case, the XML can be described as:
```xml
"/>
```
...