Data type

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資料表欄位設計時,不同資料類型,建議採用的資料型態(data type)

examples of data and suggested datatype

  • birth year
    • data type: int
    • ex: 1905 ~ 2013
    • range/limit: 108 yeas old[1][2]


  • IP(v4):
    • varchar(15)
    • ex: 255.255.255.255 [3]
    • range/limit:
  • IP range - Classless inter-domain routing (CIDR)[4]
    • 12 or 24 bytes (IPv4 and IPv6 networks)[5]
    • ex: 69.208.0.0/32
  • Chinese name:
    • 最長姓名有13個字 [6]
    • LINE姓名欄位長度限制: 15字(15個中文字或15英文字母)
  • unix timestamp:
    • bigint(10) ;
    • ex: 1328664539
    • range/limit:
  • School ID defined by MOE at Taiwan / 學校代碼[7]
    • integer: 4(university) ~ 6
    • ex: 0001(國立政治大學)、373607(臺北市立華江國小)。前面可能有零。
    • range/limit:
  • 經緯度 (經度,緯度):
    • DECIMAL(18,12)[8] or FLOAT( 10, 6 )[9]
    • ex: 37.401724,-122.114646
    • range/limit:
  • 價錢/金額
    • DECIMAL(10,2)[10]
    • ex:
    • range/limit: 0.00 ~ 99999999.99
  • 台灣縣市欄位值 下拉式選單[11]
$city = array("基隆市", "台北市", "新北市", "桃園縣", "新竹市", "新竹縣", "苗栗縣", "台中市", 
        "彰化縣", "南投縣", "雲林縣", "嘉義市", "嘉義縣", "台南市", "高雄市", "屏東縣", "台東縣", "花蓮縣", 
        "宜蘭縣", "澎湖縣", "金門縣", "連江縣");
  • 密碼
    • varchar 允許最小8個字元長度[12]


 (left blank intentionally)
* data
** data type
** ex:
** range/limit:

comparision of datatypes in different data engines

DATETIME: ex: "2013-06-13 03:33:33" MS SQL 2008, MySQL is equivalent

TIMESTAMP: MS SQL 2008 and MySQL is NOT equivalent[13] Icon_exclaim.gif

  • MS SQL 2008[14] ex: 0x00000000000007D3
  • MySQL ex: 2013-06-13 03:33:33

references

further reading