88 lines
2.3 KiB
Go
88 lines
2.3 KiB
Go
package main
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import (
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"database/sql"
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_ "modernc.org/sqlite"
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"reflect"
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"strings"
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)
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func listDrivers() {
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for _, driver := range sql.Drivers() {
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Printfln("Driver: %s", driver)
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}
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}
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var insertNewCategory *sql.Stmt
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var changeProductCategory *sql.Stmt
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func openDatabase() (db *sql.DB, err error) {
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db, err = sql.Open("sqlite", "products.db")
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if err == nil {
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Printfln("Opened database")
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insertNewCategory, _ = db.Prepare(`
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INSERT INTO categories (name) VALUES (?)
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`)
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changeProductCategory, _ = db.Prepare(`
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UPDATE products SET category = ? WHERE id = ?
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`)
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}
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return
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}
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func scanIntoStruct(rows *sql.Rows, target interface{}) (results interface{}, err error) {
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targetVal := reflect.ValueOf(target)
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if targetVal.Kind() == reflect.Ptr {
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targetVal = targetVal.Elem()
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}
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if targetVal.Kind() != reflect.Struct {
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return
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}
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colNames, _ := rows.Columns()
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colTypes, _ := rows.ColumnTypes()
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references := []interface{}{}
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var placeholder interface{}
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for i, colName := range colNames {
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Printfln("Column: %s", colName)
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// 获取字段
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colNameParts := strings.Split(colName, ".")
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field := targetVal.FieldByName(colNameParts[0])
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if field.IsValid() && field.Kind() == reflect.Struct && len(colNameParts) > 1 {
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for _, namePart := range colNameParts[1:] {
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comFunction := matchColName(namePart)
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field = field.FieldByNameFunc(comFunction)
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}
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}
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if !field.IsValid() || !colTypes[i].ScanType().ConvertibleTo(field.Type()) {
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// 字段不存在或者不可以转换
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Printfln("Column placeholder: %s", colName)
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references = append(references, &placeholder)
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} else if field.Kind() != reflect.Ptr && field.CanAddr() {
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// 字段存在并且可以转换，不为指针并且可以获取到地址
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Printfln("Column Addr: %s", colName)
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field = field.Addr()
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references = append(references, field.Interface())
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}
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}
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// 创建结果集合
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resultSlice := reflect.MakeSlice(reflect.SliceOf(targetVal.Type()), 0, 10)
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for rows.Next() {
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err = rows.Scan(references...)
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if err != nil {
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break
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}
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// 将指针转换为结构体，从而可以复制该结构体，并增加到切片中
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resultSlice = reflect.Append(resultSlice, targetVal)
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}
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results = resultSlice.Interface()
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return
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}
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func matchColName(colName string) func(string) bool {
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return func(fieldName string) bool {
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return strings.EqualFold(colName, fieldName)
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}
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}
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