Orale common table organization operation commands

Select * from USER_TAB_COLUMNS to retrieve the table structures of all tables supported by this rule (detailed information of each column)

Field tablename, column_name, data_type, data_length, nullable (null), column_id (the order of the field in the table), default_length, data_defaul, char_length (the length of the struct variable)
Select * from USER_CATALOG to retrieve the table_name and table_type fields of TABLE, VIEW, and SEQUENCE (where table_type = 'table ').
Select * from USER_COL_COMMENTS: Field tablename, column_name, comments

Select * from USER_TABLES query table information (physical)
Select * from USER_VIEWS Retrieval Attempt (physical)
Select * from USER_TAB_COMMENTS field table_name, table_type, comments table and view description
SELECT * FROM USER_ARGUMENTS
Field name object_name, packge_name, objectid,... argument_name, position, data_type, default_value, in_out, data_length (type length, data is null, VARCHAR2 is length, NUMBER is 22)
Data_type: ref cursor is the CURSOR VARCHAR2. NUMBER

Retrieve primary key and foreign key information
SELECT. constraint_name,. constraint_type,. table_name, B. column_name, c. table_name, c. column_name FROM USER_CONSTRAINTS a, USER_CONS_COLUMNS B, USER_CONS_COLUMNS c WHERE (. constraint_name = B. constraint_name AND (. constraint_type = 'P' OR. constraint_type = 'R') AND. r_constraint_name = c. constraint_name (+)