Oracle Database 12c – Page 17

July 5, 2013

OracleDB12c New Feature: Merging and Splitting Multiple Partitions

In Oracle11g, you can merge or split two partitions. This feature is enhanced in 12c to merge and split multiple partitions in a single SQL thus reducing the maintenance operations. When merging range partitions, they must be adjacent.

Merging Partitions Example:

ALTER TABLE SALESDATA
MERGE PARTITIONS S2012Q1, S2012Q2, S2012Q3, S2012Q4 INTO S2012;

If range partitions are merged, you may use the “TO” clause.

ALTER TABLE SALESDATA
MERGE PARTITIONS S2012Q1 TO S2012Q4 INTO S2012;

Read more about this feature and restrictions in Oracle Documentation.

Splitting Partitions Example:

ALTER TABLE SALESDATA SPLIT PARTITION S2014 INTO
(PARTITION S2014Q1 VALUES LESS THAN TO_DATE('01-APR-14','DD-MON-YY')),
(PARTITION S2014Q2 VALUES LESS THAN TO_DATE('01-JUL-14','DD-MON-YY')),
(PARTITION S2014Q3 VALUES LESS THAN TO_DATE('01-OCT-14','DD-MON-YY')),
(PARTITION S2014Q4 );

OracleDB12c New Feature: Use of Sequence Value in Column DEFAULT

Happy 4th of July!

In the 12c new feature a day series, I discussed the “Identity Column” feature yesterday. Extension to that feature is now you can use sequence pseudo-column NETXTVAL or CURRVAL as DEFAULT value for a column in table definition. In the prior releases to be able to do this, a trigger and some coding was required…

If the sequence is owned by another user, appropriate access should be granted on the sequence [privilege, synonym, qualify with schema name].

You can have only one IDENTITY column per table, buy you may create more than one column with DEFAULT sequence values.

Example:

CREATE TABLE T1 (
X1 NUMBER DEFAULT SCOTT.MYSEQ.NEXTVAL,
X2 VARCHAR2);