When the table suffix is non numeric, the insertion operation will report an error when generating the primary key ID

[mocanxi]

Solving the problem of generating primary key errors when the table suffix is a string eg:

type FileRecord struct {
    ID        int64  `gorm:"primary_key;column:id"`
    Project   string `gorm:"column:project"`
    UserID    int64  `gorm:"column:user_id"`
    ProductID int64  `gorm:"column:product_id"`
}

func (FileRecord) TableName() string {
    return "file_record"
}

middleware := sharding.Register(sharding.Config{
        ShardingKey: "project",
        ShardingAlgorithm: func(value interface{}) (suffix string, err error) {
            if project, ok := value.(string); ok {
                return fmt.Sprintf("_%s", project), nil
            }
            return "", errors.New("invalid project")
        },
        NumberOfShards: 8,
        //PrimaryKeyGenerator: sharding.PKSnowflake,
    }, "file_record")
    db.Use(middleware)

    // 插入数据
    err = db.Create(&FileRecord{UserID: 221, Project: "a"}).Error
    if err != nil {
        fmt.Println(err)
    }

Error message: strconv.Atoi: parsing "a": invalid syntax

Now, ShardingSuffixs should be set. eg:

middleware := sharding.Register(sharding.Config{
        ShardingKey: "project",
        ShardingAlgorithm: func(value interface{}) (suffix string, err error) {
            if project, ok := value.(string); ok {
                return fmt.Sprintf("_%s", project), nil
            }
            return "", errors.New("invalid project")
        },
        ShardingSuffixs: func() (suffixs []string) {
            return []string{"a", "b", "c", "d", "e", "f"}
        },
        NumberOfShards:      8,
        PrimaryKeyGenerator: sharding.PKSnowflake,
    }, "file_record")
    db.Use(middleware)