This article presents simple methods to write or read CLOB to/from file using following packages:
- DBMS_XSLPROCESSOR
- DBMS_LOB
Dump Upload CLOB to, from file in Oracle
2
Category Archives: Important learnings
Using CLOB in external tables – KUP-04026
This article presents solution for “KUP-04026: field too long for datatype” for external tables. Usually it happens when you want to read data for CLOB columns.
QB_NAME – control execution plans in views
Typical problem that you can encounter during tuning is how to change explain plan inside complex view or inside a subquery for your sql statements. QB_NAME hints helps to do it. It can define a name for a query block. This name can then be used in another query block to hint tables appearing in the named query block.
Oracle PGA monitoring using ASH and AWR
Article presents how to create simple report to monitor PGA in Oracle database using ASH or AWR as source.
PGA is dedicated memory structure in SGA stores stores following areas:
Cursors and private sql areas
- opened cursors, links to shared SQL areas in shared pool
- bind variable for cursors
- query execution state information
SQL work areas
- sort operations (order by, group-by, rollup, window function)
- hash-join
- bitmap merge
- bitmap create
Transform SQL to XML in Oracle
This article presents methods to transform an SQL to XML format with minimum effort possible.
Let’s take simple SQL
SELECT owner, table_name FROM dba_tables WHERE table_name LIKE 'USER%' and owner='SYS'; OWNER TABLE_NAME ------------------------------ ------------------------------ SYS USER_HISTORY$ SYS USER_ASTATUS_MAP SYS USER$
and try to transform it into XML format
WITH clause and hints MATERIALIZE and INLINE
WITH clause is commonly used to simplify SQL statements. This article shows impact of dedicated hints MATERIALIZE and INLINE for processing data with WITH clause.
Oracle GANTT report in SQL
This article presents how to generate GANTT reports using sql.
A GANTT charts are commonly used in project management or batch processing, as one of the most popular and useful ways of showing activities (tasks or events) displayed against time. On the left of the chart is a list of the activities and along the top is a suitable time scale. Each activity is represented by a bar; the position and length of the bar reflects the start date, duration and end date of the activity. This allows you to see at a glance:
- What the various activities are
- When each activity begins and ends
- How long each activity is scheduled to last
- Where activities overlap with other activities, and by how much
- The start and end date of the whole project
ORA_HASH and CLOB problem
This article focus on ORA_HASH function in Oracle. This function computes a hash value for a given expression.
SELECT
ORA_HASH('test') oh,
ORA_HASH('test1') oh1
FROM dual;
OH OH1
---------- ----------
2662839991 1531096017
ORA-22828: input pattern or replacement parameters exceed 32K size limit
This short article presents how to solve ORA-22828 error.
ORA-22828 happens when you try to replace part of a CLOB with a CLOB bigger than 32K using standard functions like REPLACE, REGEXP_REPLACE.
String split methods
This article show how to translate string separated by a character
'STR1,STR2,STR3,STR4'
into rows
STR_REC ------------------- STR1 STR2 STR3 STR4