Internal LOBs-Datatypes

Starting with Oracle Database 11g, Oracle introduced a new underlying architecture for LOBs known as SecureFiles. The prior existing LOB architecture is known as BasicFiles. By default in 11g, when you create a LOB, it will be created as a BasicFiles LOB. Starting with Oracle 12c, when creating a LOB column in an ASSM-managed tablespace,
Read more

LOB Tablespace-Datatypes

The CREATE TABLE statement returned from DBMS_METADATA for both the SecureFiles and BasicFiles included the following:LOB (“TXT”) STORE AS … ( TABLESPACE “USERS” … The TABLESPACE specified here is the tablespace where the LOBSEGMENT and LOBINDEX will be stored, and this may be different from the tablespace where the table itself resides. That is, the
Read more

Range Partitioning-Partitioning

The first type we will look at is a range partitioned table. The following CREATE TABLE statement creates a range partitioned table using the column RANGE_KEY_COLUMN. All data with a RANGE_KEY_COLUMN strictly less than 01-JAN-2021 will be placed into the partition PART_1, and all data with a value strictly less than 01-JAN-2022 (and greater than
Read more

TIMESTAMP WITH TIME ZONE Type-Datatypes

The TIMESTAMP WITH TIME ZONE type inherits all of the qualities of the TIMESTAMP type and adds time zone support.The TIMESTAMP WITH TIME ZONE type consumes 13 bytes of storage, with the extra 2 bytes being used to preserve the time zone information. It differs from a TIMESTAMP structurally only by the addition of these
Read more

Creating a BasicFiles LOB-Datatypes

In 12c and above, to create a BasicFiles LOB, you’ll need to use the STORE AS BASICFILE syntax: SQL> create table t( id int primary key,txt clob)segment creation immediatelob(txt) store as basicfile;Table created. Using the DBMS_METADATA package, we can see the details of a BasicFiles LOB:SQL> select dbms_metadata.get_ddl( ‘TABLE’, ‘T’ ) from dual;DBMS_METADATA.GET_DDL(‘TABLE’,’T’) CREATE TABLE
Read more

IN ROW Clause-Datatypes

The CREATE TABLE statement returned from DBMS_METADATA earlier for both theSecureFiles and BasicFiles included the following:LOB (“TXT”) STORE AS … (… ENABLE STORAGE IN ROW … This controls whether the LOB data is always stored separate from the table in the LOBSEGMENT or if it can sometimes be stored right in the table itself without
Read more

Read Consistency for LOBs-Datatypes

In previous chapters, we’ve discussed read consistency, multiversioning, and the role that undo plays in that. Well, when it comes to LOBs, the way read consistency is implemented changes. The LOBSEGMENT does not use undo to record its changes; rather, it versions the information directly in the LOBSEGMENT itself. The LOBINDEX generates undo just as
Read more
Copyright All right reserved
BACK TO TOP