How to Lock Table and Unlock Table
Lock Table Oracle provides LOCK TABLE statements to let users lock table as their needs. For example: SQL> conn hr/hr@orclpdb Connected. SQL> lock table employees… Read More »How to Lock Table and Unlock Table
Data Definition Language (DDL)
How to CTAS Tablespace
Create Table As Select Tablespace Without specifying tablespace, Create Table As Select (CTAS) will go to the default tablespace of the user. How about specifying… Read More »How to CTAS Tablespace
DBMS_METADATA.GET_DDL Table
Get Table DDL To retrieve the definition (Data Definition Language, DDL) of a table, we use the function DBMS_METADATA.GET_DDL to make it. Let's see an… Read More »DBMS_METADATA.GET_DDL Table
What is LAST_DDL_TIME?
LAST_DDL_TIME Generally speaking, LAST_DDL_TIME means the last date time of the object definition changed by Data Definition Language (DDL). But sometimes, it's been updated with… Read More »What is LAST_DDL_TIME?
How to Resolve Toad Error ORA-00904: "REF": invalid identifier
Tried to display "Script" (DDL) of a table in Toad for Oracle, we saw ORA-00904: "REF": invalid identifier. Typically, ORA-00904 is an unmatched column issue,… Read More »How to Resolve Toad Error ORA-00904: "REF": invalid identifier
How to Get DDL of Sequence from ALL_SEQUENCES
You don't have to export and import sequences by data pump, you can compose the creation statements by querying ALL_SEQUENCES: [oracle@primary01 oracle]$ vi compose_create_sequence.sql set… Read More »How to Get DDL of Sequence from ALL_SEQUENCES
How to Get DDL of Synonym from ALL_SYNONYMS
You don't have to export and import public synonyms by data pump, you can compose the creation statements by querying ALL_SYNONYMS:: [oracle@primary01 oracle]$ vi compose_create_or_replace_synonym.sql… Read More »How to Get DDL of Synonym from ALL_SYNONYMS
Prepare Tablespace before Data Migration
In the beginning of data migration, we usually recreate some tablespaces to accommodate data from the source. The best way to do this is to… Read More »Prepare Tablespace before Data Migration
Truncate vs Delete in Oracle
Truncate vs Delete Here I compare the differences between TRUNCATE and DELETE an entire table in the following chart. Question Truncate Table Delete From DDL… Read More »Truncate vs Delete in Oracle
DB Link, How and Why
What is DB Link? A database link is a kind of schema object in a database that enables users to access and manipulate objects on… Read More »DB Link, How and Why