Shulou(Shulou.com)06/01 Report--

Several common data types in oracle:

The length of the char is fixed, with a maximum length of 2K bytes. For example, if you define char (20), even if you insert abc with less than 20 bytes, the database will automatically add 17 spaces after abc to make up 20 bytes.

Chinese accounts for two bytes in char, while English accounts for one, so you can only save 20 letters or 10 Chinese characters in char (20).

Varchar is suitable for non-fixed length, with a maximum length of 4K bytes. For example, if you define varchar (20), when you insert abc, it only occupies 3 bytes in the database.

Long is used to store variable length character data with a maximum length of 2GB

Number, which is used to store integer or floating-point values. Where p is all digits and s is decimal place. The value range of Number (5 quotient 2) is 999.99.

Date is used to store date data

SQL > select to_char (sysdate,'yyyy-mm-dd') from dual

TO_CHAR (SYSDATE,'YYYY-MM-DD')

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2014-12-24

SQL > select to_char (sysdate,'yyyy-mm-dd hh34:mi:ss') from dual

TO_CHAR (SYSDATE,'YYYY-MM-DDHH24:MI:SS')

2014-12-24 06:36:18

SQL > select to_date (sysdate,'yyyy-mm-dd') from dual

TO_DATE (SYSDATE

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14-DEC-24

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