Oracle RDBMS: Extracting the Table, Index & View Definitions (DDL) and Indexed Columns

(Reproducing a 30 month old blog post from my other blog at blogger. Source URL:
    http://technopark02.blogspot.com/2007/05/oracle-how-to-get-tableview-definition.html
)

Q: How to extract the table definition (DDL statement) from an Oracle database without having to go through a stack of dictionary views?

A: By calling the GET_DDL() function of metadata package DBMS_METADATA.

Syntax:
select DBMS_METADATA.GET_DDL('TABLE','<table_name>') from DUAL;

eg.,
SQL> set long 1000
SQL> set pagesize 0

SQL> select DBMS_METADATA.GET_DDL('TABLE','PERSON') from DUAL;

  CREATE TABLE "FS890"."PERSON"
   (    "SSN" VARCHAR2(12),
        "FIRST_NAME" VARCHAR2(25),
        "LAST_NAME" VARCHAR2(25),
        "STREET" VARCHAR2(40),
        "CITY" VARCHAR2(30),
        "STATE" VARCHAR2(30),
        "ZIP" VARCHAR2(15),
        "COUNTRY" VARCHAR2(35)
   ) PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING
  STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT
)  TABLESPACE "PSDEFAULT"



Q: How to extract the index definition (DDL statement) from an Oracle database for a given index nam?

A: By calling the GET_DDL() function of metadata package DBMS_METADATA.

Syntax:
select DBMS_METADATA.GET_DDL('INDEX','<index_name>') from DUAL;

eg.,
SQL> create index PERSON_IDX on PERSON ( SSN ); 

Index created.

SQL> set long 1000
SQL> set pagesize 0

SQL> select  DBMS_METADATA.GET_DDL('INDEX','PERSON_IDX') from DUAL;

  CREATE INDEX "FS890"."PERSON_IDX" ON "FS890"."PERSON" ("SSN")
  PCTFREE 10 INITRANS 2 MAXTRANS 255
  STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)
  TABLESPACE "PSDEFAULT"

Note:

If the interest is only to get the indexed column names for an index, simply query COLUMN_NAME of table USER_IND_COLUMNS.

Syntax:
select COLUMN_NAME from USER_IND_COLUMNS where INDEX_NAME = '<index_name>';

eg.,
SQL> column COLUMN_NAME format A15
SQL> select COLUMN_NAME from USER_IND_COLUMNS where INDEX_NAME = 'PERSON_IDX';

COLUMN_NAME
---------------
SSN



Q: Given a view name, how do we get the definition of the view? i.e., how to get the corresponding DDL statement that was used to create the view?

A: Query the TEXT column of table DBA_VIEWS.

Syntax:
SQL> set long 10000

SQL> select TEXT
  2  FROM DBA_VIEWS
  3  where OWNER = '<owner_name>'
  4  and VIEW_NAME  = '<view_name>';
Here is an example:
% sqlplus fs890/fs890@fs890

SQL> create table PERSON (
  2  SSN        VARCHAR2(12),
  3  FIRST_NAME VARCHAR2(25),
  4  LAST_NAME  VARCHAR2(25),
  5  STREET     VARCHAR2(40),
  6  CITY       VARCHAR2(30),
  7  STATE      VARCHAR2(30),
  8  ZIP        VARCHAR2(15),
  9  COUNTRY    VARCHAR2(35));

Table created.

SQL> create view PERSON_VW as
  2  select SSN, FIRST_NAME, LAST_NAME from PERSON;

View created.

SQL> set long 1000
SQL> select TEXT
  2  from DBA_VIEWS
  3  where OWNER = 'FS890'
  4  and VIEW_NAME  = 'PERSON_VW';

TEXT
--------------------------------------------------------------------------------
SELECT SSN, FIRST_NAME, LAST_NAME FROM PERSON



Q: How to find the schema name and the DB user name from an active session?

A: Run the following query:

select sys_context('USERENV', 'SESSION_USER') SESSION_USER, sys_context('USERENV', 'CURRENT_SCHEMA') CURRENT_SCHEMA from dual;

Alternatively run select USER from DUAL; to find the current {session} user name.

sys_context() function returns the value of parameter associated with the context namespace. USERENV is an Oracle provided namespace that describes the current session. Check the table Predefined Parameters of Namespace USERENV for the list of parameters and the expected return values.

eg.,
SQL> column SESSION_USER format A15
SQL> column CURRENT_SEHEMA format A15

SQL> select sys_context('USERENV', 'SESSION_USER') SESSION_USER, 
  2  sys_context('USERENV', 'CURRENT_SCHEMA') CURRENT_SCHEMA from dual;

SESSION_USER    CURRENT_SCHEMA
--------------- ---------------
FS890           FS890

SQL> column USER format A6

SQL> select USER from DUAL;

USER
------
FS890



Note:

Be aware that there are multiple ways of extracting the same piece of information from an Oracle database. I just provided the ones that I frequently use as part of my work.

Comments:

but not getting full info. like
SQL> select DBMS_METADATA.GET_DDL('TABLE','TEST') from DUAL;

DBMS_METADATA.GET_DDL('TABLE','TEST')
---------------------------------------------------
CREATE TABLE "USER_1"."TEST"
( "REGION" VARCHAR2(50),
"CITY" V

but we need full defination.

Posted by guest on November 28, 2012 at 09:29 PM PST #

how to see the peoplesoft application data table structure in RDBMS catalog tables.

Posted by guest on October 03, 2013 at 11:48 PM PDT #

thank you very much. now i know the connection with metadata.

Posted by guest on October 21, 2013 at 12:26 AM PDT #

use
SQL> set long 1000
SQL> set pagesize 0

to see the full output

Posted by yudhi on November 14, 2013 at 12:57 AM PST #

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