golang xorm reverse

(This article will introduce how to use the ORM framework xorm of the Go language to implement the inversion operation)

xorm is one of the commonly used ORM frameworks in the Go language. It supports many databases, including MySQL, PostgreSQL, SQLite, Oracle, and more. When using xorm for database operations, we often need to perform record reversal operations, that is, reversing records in a table into records in another table. The following will introduce how to use xorm to implement the reversal operation in the Go language.

First, we need to define our data model. Suppose we have a User model, which contains fields such as id, name, email, etc. We need to define two structures, representing the User table and ReverseUser table respectively.

type User struct {
    Id    int64  `xorm:"'id' pk autoincr"`
    Name  string `xorm:"'name'"`
    Email string `xorm:"'email'"`
}

type ReverseUser struct {
    Id      int64  `xorm:"'id' pk autoincr"`
    Name    string `xorm:"'name'"`
    Email   string `xorm:"'email'"`
    Reverse string `xorm:"'reverse'"`
}

It should be noted that we have added a new field Reverse in ReverseUser to store the reversed data.

Next, we need to use xorm for database operations. First, define two engines, corresponding to the User table and ReverseUser table:

userEngine, _ := xorm.NewEngine("mysql", "username:password@tcp(127.0.0.1:3306)/user_db?charset=utf8")
userEngine.ShowSQL(true)
reverseEngine, _ := xorm.NewEngine("mysql", "username:password@tcp(127.0.0.1:3306)/reverse_user_db?charset=utf8")
reverseEngine.ShowSQL(true)

It should be noted that the database connection information here needs to be modified according to the actual situation.

Next, we need to convert the records in the User table to records in the ReverseUser table. This can be achieved with the following code:

users := make([]User, 0)
err := userEngine.Find(&users)
if err != nil {
    fmt.Println(err)
    return
}

reverseUsers := make([]ReverseUser, 0)
for _, user := range users {
    reverseUsers = append(reverseUsers, ReverseUser{
        Name:    user.Name,
        Email:   user.Email,
        Reverse: reverseString(user.Name),
    })
}

err = reverseEngine.Insert(&reverseUsers)
if err != nil {
    fmt.Println(err)
    return
}

First, we use userEngine to get all the records from the User table. Then, iterate through each User record, convert it to a ReverseUser record, and add it to the reverseUsers slice. Finally, use reverseEngine to insert the records in reverseUsers into the ReverseUser table.

It should be noted that we store the reverse form of the name in the Reverse field of ReverseUser, which needs to be implemented through a function. The following is the implementation of this function:

func reverseString(str string) string {
    runes := []rune(str)
    for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
        runes[i], runes[j] = runes[j], runes[i]
    }
    return string(runes)
}

This function receives a string as a parameter and returns the reversed form of the string.

Finally, we need to do some finishing work and shut down the database engine:

defer userEngine.Close()
defer reverseEngine.Close()

The above code implements the complete process of using xorm to perform the reversal operation. It should be noted that this method is suitable for small data tables and is not suitable for large data tables, because maintaining large slices in memory may cause performance problems. If your data table is very large, use appropriate paging techniques.

Summary:

In the Go language, it is very convenient to use the xorm framework to implement data reversal operations. We only need to define the data model, create a database engine, convert the data into the required format, and then insert it into the database. At the same time, we need to pay attention to some details, such as canceling the structure of the table, etc., to ensure that our code works properly.

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