Monday, 30 July 2018

How to know last login info on the system?

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-> show all records $ last -> show all records page by page $ last | more -> show first 10 records $ last | head -> sho...
Wednesday, 18 July 2018

How to change service name?

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e.g. current service name: postgresql.service desired service name: postgresql-9.1.service Run following commands to change service name...
Friday, 13 July 2018

How to solve remote connection error cause of iptables/firewalld service?

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Case Machine A (192.168.1.2) wants to connect on Machine B (192.168.1.5) by database port. Action In Machine A; # su - postgres $ psql...

How to solve database module error?

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Action # ansible-playbook -i myhosts example.yml -v Error TASK [example role : example task] ******************* fatal: [local]: FAILED...
Friday, 6 July 2018

How to prevent sleep mode on laptop when lid closes?

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Press Window Key then type "Power Options" and click on it -> Click  "Choose what closing the lid does" -> Set ...
Friday, 29 June 2018

How to run a SQL query/statement in a task?

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You are able to run a SQL query/statement with "echo" command by  shell module for the ansible task. # an example task for sql ...

benefit of "gather_facts: no" setting

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If you do not need any facts for your variables, you can run your playbook more fast via gather_facts setting. For this, just add followi...
Friday, 18 May 2018

"database "example" is being accessed by other users" solution

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Action postgres=# drop database example ; Error ERROR:  database " example " is being accessed by other users DETAIL:  There ...
Sunday, 6 May 2018

How to backup database in XE?

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It is very simple to backup your database in Oracle XE with already prepared .bat file quickly. Steps; Press Windows Key -> Type ...
Friday, 27 April 2018

e.g. truncate table cascade

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Preparation of Test Data test=#  create table employees (id integer, name varchar, department_id integer); test=#  create table departm...
Thursday, 26 April 2018

e.g. fetching JSON data

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Preparation of Test Data test=#  create table  T_JSON_DATA  (id INTEGER, body JSON); test=# insert into T_JSON_DATA values (1, '{ ...
Wednesday, 25 April 2018

ORA-02292 solution

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Preparation -- Insert test data into DEPARTMENT and EMPLOYEES tables. SQL> INSERT INTO DEPARTMENTS VALUES ( 280 ,'New Department...
Thursday, 19 April 2018

e.g. count and distinct aggregate functions

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examples; count (1) - count(*) - count(column_name) - count( distinct (column_name)) e.g. count aggregate function SQL> SELECT     ...
Wednesday, 11 April 2018

ORA-02449 solution

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Preparation SQL> CREATE TABLESPACE EXAMPLE_TS DATAFILE   'C:\ORACLEXE_XE\APP\ORACLE\ORADATA\XE\example_01.dbf' SIZE 512K REUSE...

ORA-01549 solution

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Preparation SQL> CREATE TABLESPACE EXAMPLE_TS DATAFILE   'C:\ORACLE_XE\APP\ORACLE\ORADATA\XE\example_01.dbf' SIZE 512K REUSE ...
Monday, 9 April 2018

e.g. pivot clause

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Preparation  * Define column names for pivot table SQL> SELECT LISTAGG (           '''' || JOB_ID || '''...
Friday, 6 April 2018

How to use SPOOL command in Oracle?

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WINDOWS e.g. SQL>  sqlplus / as sysdba; SQL> SET LINESIZE 200; SET PAGESIZE 100; -- define a output file for writing SPOOL ...
Tuesday, 3 April 2018

What are pencil hardness grading scales?

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2H -> H -> F -> HB -> B -> 2B H means Hard (hard-tipped) B means Bold  (soft-tipped) F means Fine Info: from left to r...
Friday, 30 March 2018

What is implicit commit?

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After every DDL operation, implicit commit occurs such as while defining a new table. e.g. CREATE TABLE HR.EXAMPLE(ABC char(1)); Also w...

blob vs bfile data types

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BLOB (binary large objects) stores unstructured binary large objects. It is often used for graphic images, video clips, and sounds. The BLO...