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Oracle数据类型限制

本帖由 tc0082016-12-09 发布。版面名称:后端开发

  1. tc008

    tc008 New Member

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    Oracle数据库一向给我们功能强大的印象,殊不知Oracle内部也是有各种限制的.
    今天我们就说说数据类型的限制,也就是数据类型的取值范围:

    数据类型
    限制
    注释
    BFILE
    Maximum size: 4 GB 文件最大4G
    The maximum number of BFILEs is limited by the value of the SESSION_MAX_OPEN_FILES initialization parameter, which is itself limited by the maximum number of open files the operating system will allow.

    BFILE最大可打开数量由参数SESSION_MAX_OPEN_FILES 决定
    而SESSION_MAX_OPEN_FILES参数的最大值由操作系统允许打开的最大文件数量所决定
    Maximum size of a file name: 255 characters
    文件名最长255字符
    Maximum size of a directory name: 30 characters
    目录名最长30字符
    Maximum number of open BFILEs: see Comments
    最大可以同时打开的熟练参见注释
    BLOB
    Maximum size: (4 GB - 1) * DB_BLOCK_SIZE initialization parameter (8 TB to 128 TB)
    最大大小为 (4 GB - 1) * DB_BLOCK_SIZE.
    根据块大小不同范围为8TB到128TB.
    The number of LOB columns per table is limited only by the maximum number of columns per table
    一个表中可包含的LOB列的多少由表中最大列数量决定
    CHAR
    Maximum size: 2000 bytes
    CHAR类型最长为2000字节
    None
    CHAR VARYING
    Maximum size: 4000 bytes
    CHAR 变量最长为4000 字节
    None
    CLOB
    Maximum size: (4 GB - 1) * DB_BLOCK_SIZE initialization parameter (8 TB to 128 TB)
    The number of LOB columns per table is limited only by the maximum number of columns per table
    The number of LOB columns per table is limited only by the maximum number of columns per table (that is, 1000Footref ).
    Literals (characters or numbers in SQL or PL/SQL)
    Maximum size: 4000 characters
    字面值:最长4000个字节
    None
    LONG
    Maximum size: 2 GB - 1
    最长大小为 2GB-1
    Only one LONG column is allowed per table.
    NCHAR
    Maximum size: 2000 bytes
    最长大小为2000字节
    None
    NCHAR VARYING
    Maximum size: 4000 bytes, or 32767 bytes if the MAX_STRING_SIZE initialization parameter is set to EXTENDED
    NCHAR 变量为4000 如果设置MAX_STRING_SIZE为EXTENDED,最大可支持32767个字节
    None
    See Also: "MAX_STRING_SIZE" initialization parameter for additional details
    NCLOB
    Maximum size: (4 GB - 1) * DB_BLOCK_SIZE initialization parameter (8 TB to 128 TB)
    最大大小为 (4 GB - 1) * DB_BLOCK_SIZE.
    根据块大小不同范围为8TB到128TB.
    The number of LOB columns per table is limited only by the maximum number of columns per table (that is, 1000Footref ).
    一个表中可包含的LOB列的多少由表中最大列数量决定
    NUMBER
    最大值999...(38 9's) x10125
    Can be represented to full 38-digit precision (the mantissa)
    最小值-999...(38 9's) x10125
    Can be represented to full 38-digit precision (the mantissa)
    Precision(精度)
    38 significant digits
    None
    RAW
    Maximum size: 2000 bytes, or 32767 bytes if the MAX_STRING_SIZE initialization parameter is set to EXTENDED
    最大大小为2000字节,如果设置MAX_STRING_SIZE参数为 EXTENDED则为32767
    None
    See Also: "MAX_STRING_SIZE" initialization parameter for additional details
    VARCHAR
    Maximum size: 4000 bytes
    最长为4000字节
    None
    VARCHAR2
    Maximum size: 4000 bytes, or 32767 bytes if the MAX_STRING_SIZE initialization parameter is set to EXTENDED
    最大大小为4000字节,如果设置MAX_STRING_SIZE参数为 EXTENDED则为32767
    None
    See Also: "MAX_STRING_SIZE" initialization parameter for additional details
    原文:http://t.bosenrui.com/dba/a9ad307866880646d66762fb2a349682.html
     
  2. ﹏譆揂嶼妳ゞ

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  3. 和商投资

    和商投资 Member

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