Golang QueryDialect示例

示例#1

// NewEngine new a db manager according to the parameter. Currently support four
// drivers
func NewEngine(driverName string, dataSourceName string) (*Engine, error) {
	regDrvsNDialects()
	driver := core.QueryDriver(driverName)
	if driver == nil {
		return nil, fmt.Errorf("Unsupported driver name: %v", driverName)
	}

	uri, err := driver.Parse(driverName, dataSourceName)
	if err != nil {
		return nil, err
	}

	dialect := core.QueryDialect(uri.DbType)
	if dialect == nil {
		return nil, fmt.Errorf("Unsupported dialect type: %v", uri.DbType)
	}

	db, err := core.Open(driverName, dataSourceName)
	if err != nil {
		return nil, err
	}

	err = dialect.Init(db, uri, driverName, dataSourceName)
	if err != nil {
		return nil, err
	}

	engine := &Engine{
		db:            db,
		dialect:       dialect,
		Tables:        make(map[reflect.Type]*core.Table),
		mutex:         &sync.RWMutex{},
		TagIdentifier: "xorm",
		TZLocation:    time.Local,
	}

	logger := NewSimpleLogger(os.Stdout)
	logger.SetLevel(core.LOG_INFO)
	engine.SetLogger(logger)
	engine.SetMapper(core.NewCacheMapper(new(core.SnakeMapper)))

	runtime.SetFinalizer(engine, close)

	return engine, nil
}

示例#2

// DumpAll dump database all table structs and data to w with specify db type
func (engine *Engine) dumpTables(tables []*core.Table, w io.Writer, tp ...core.DbType) error {
	var dialect core.Dialect
	if len(tp) == 0 {
		dialect = engine.dialect
	} else {
		dialect = core.QueryDialect(tp[0])
		if dialect == nil {
			return errors.New("Unsupported database type.")
		}
		dialect.Init(nil, engine.dialect.URI(), "", "")
	}

	_, err := io.WriteString(w, fmt.Sprintf("/*Generated by xorm v%s %s, from %s to %s*/\n\n",
		Version, time.Now().In(engine.TZLocation).Format("2006-01-02 15:04:05"), engine.dialect.DBType(), dialect.DBType()))
	if err != nil {
		return err
	}

	for i, table := range tables {
		if i > 0 {
			_, err = io.WriteString(w, "\n")
			if err != nil {
				return err
			}
		}
		_, err = io.WriteString(w, dialect.CreateTableSql(table, "", table.StoreEngine, "")+";\n")
		if err != nil {
			return err
		}
		for _, index := range table.Indexes {
			_, err = io.WriteString(w, dialect.CreateIndexSql(table.Name, index)+";\n")
			if err != nil {
				return err
			}
		}

		rows, err := engine.DB().Query("SELECT * FROM " + engine.Quote(table.Name))
		if err != nil {
			return err
		}
		defer rows.Close()

		cols, err := rows.Columns()
		if err != nil {
			return err
		}
		if len(cols) == 0 {
			continue
		}
		for rows.Next() {
			dest := make([]interface{}, len(cols))
			err = rows.ScanSlice(&dest)
			if err != nil {
				return err
			}

			_, err = io.WriteString(w, "INSERT INTO "+dialect.Quote(table.Name)+" ("+dialect.Quote(strings.Join(cols, dialect.Quote(", ")))+") VALUES (")
			if err != nil {
				return err
			}

			var temp string
			for i, d := range dest {
				col := table.GetColumn(cols[i])
				if d == nil {
					temp += ", NULL"
				} else if col.SQLType.IsText() || col.SQLType.IsTime() {
					var v = fmt.Sprintf("%s", d)
					if strings.HasSuffix(v, " +0000 UTC") {
						temp += fmt.Sprintf(", '%s'", v[0:len(v)-len(" +0000 UTC")])
					} else {
						temp += ", '" + strings.Replace(v, "'", "''", -1) + "'"
					}
				} else if col.SQLType.IsBlob() {
					if reflect.TypeOf(d).Kind() == reflect.Slice {
						temp += fmt.Sprintf(", %s", dialect.FormatBytes(d.([]byte)))
					} else if reflect.TypeOf(d).Kind() == reflect.String {
						temp += fmt.Sprintf(", '%s'", d.(string))
					}
				} else if col.SQLType.IsNumeric() {
					switch reflect.TypeOf(d).Kind() {
					case reflect.Slice:
						temp += fmt.Sprintf(", %s", string(d.([]byte)))
					default:
						temp += fmt.Sprintf(", %v", d)
					}
				} else {
					s := fmt.Sprintf("%v", d)
					if strings.Contains(s, ":") || strings.Contains(s, "-") {
						if strings.HasSuffix(s, " +0000 UTC") {
							temp += fmt.Sprintf(", '%s'", s[0:len(s)-len(" +0000 UTC")])
						} else {
							temp += fmt.Sprintf(", '%s'", s)
						}
					} else {
						temp += fmt.Sprintf(", %s", s)
					}
				}
			}
			_, err = io.WriteString(w, temp[2:]+");\n")
			if err != nil {
				return err
			}
		}
	}
	return nil
}