Some SQL commands commonly used in the Oralce database (add field annotations, modify data, and so on)

Recently began to contact Oralce, organized a few recent SQL commands commonly used in PL

1. Modify the data in the table

write the query statement and condition, and then add "for Update", "for Update" is to get oacle Modify permission, execute this query statement, query the corresponding record

Select *  from  for UPDATE

2. Adding fields and annotations to a table

Alter Table Add VARCHAR2 (a);   -- Add Field  on column  is ' Number of affairs ';   -- Add Comment

3. modifying field data types

Alter Table  Number (ten)

4. Know a field name, reverse lookup table containing this field

as follows, know the field name "Identity_type" and use the following statement to find out which table contains this field

SELECT *  from WHERE = ' Gd_base '  and   like ' identity_type% ';

5. When performing an update operation, if There is no commitat the bottom of the SQL statement, you will need to manually click the "Submit" button after execution

also Note When executing the SQL statement that the data to be updated is exactly the same as the fields that exist in the database

Some SQL commands commonly used in the Oralce database (add field annotations, modify data, and so on)