Oracle Data Type Parsing

Oracle Data Type parsing char: a maximum of 2000 characters, less than space filling. It is highly efficient to use the char type for fields with fixed length and frequently queried, because the exact match of the fixed length is not a waste of space. Such as mobile phone number of Gender id card. Varchar2: a maximum of 4000 characters, variable length. Save space. Clob: 4 GB, large object type. Blob: 4 GB, binary data. Such as storing sound images, applicable to data with high confidentiality. The path for storing folder databases in the actual project. Www.2cto.com number: an integer or decimal number between the power 38 of-10 and the power 38 of 10. Number (5, 2) --- retain the five effective decimal places of two digits. -999.99 ~ 999.99 number (5) --- 5-digit integer. -99999 ~ 99999 date: year, month, day, hour, minute, and second. The interval between two events is second. Use to_char conversion packaging:
* Default date format: 'dd -- MON--YY '(-10) generally, the date field to_char is inserted into the record first. Timestamp: timestamp, which is an extension of oracle9i to date type. Accurate to decimal seconds. You can also use the to_char conversion packaging and use the cast function to convert from the date type to the timestamp type:
* If you move the date field in one table to the timestamp field in another table, oracle automatically converts the field. * The trunc function does not support the timestamp type. Author: clownfish 0703