User_tab_cols and User_tab_columns Differences in Oracle

In Oracle these two systems are very important, especially when doing dynamic SQL based on these two views to do the query, and then to do the corresponding actions: such as field length, non-null constraints. But what is the difference between these two views?

By looking at the metadata in Oracle, you can clearly see the difference between them:

reate or replace view sys.user_tab_columns as

Select table_name, COLUMN_NAME, Data_type, Data_type_mod, Data_type_owner, Data_length, Data_precision, DATA_SCALE, NULLABLE, column_id, Default_length, Data_default, num_distinct, Low_value, High_value, DENSITY, Num_nulls, NU M_buckets, last_analyzed, Sample_size, Character_set_name, Char_col_decl_length, Global_stats, USER_STATS, AVG _col_len, Char_length, char_used, V80_fmt_image, data_upgraded, histogram from user_tab_cols where HIDDEN_COLUMN = ' NO ' after an Oracle has indexed the table, a field is automatically added to the list, but this field is identified with Yes in the Hidden_column in User_tab_cols.

User_tab_cols and User_tab_columns Differences in Oracle