This article presents how to install Oracle 12C(12.2) Release 2 on Oracle Enterprise Linux 7 (OEL7).
Read following article how to install Oracle Enterprise Linux 7: Install Oracle Linux 7 (OEL7) (for comfort set 4G memory for your virtual machine before proceeding with Oracle software installation).
Software for 12CR2 is available on OTN or edelivery
In previous releases there was always problem with function LISTAGG. If list of concatenated expression exceeds maximum length supported by VARCHAR2 type, then ORA-01489 is raised.
In new version Oracle Database Release 12.2 addressed this issue by adding extra clause ON OVERFLOW TRUNCATE to hide this error. In my opinion it’s not full solution but in some cases can be useful.
LISTAGG ( [ALL] <measure_column> [,<delimiter>]
[ON OVERFLOW TRUNCATE [truncate_literal] [WITH | WITHOUT COUNT] |
ON OVERFLOW ERROR])
WITHIN GROUP (ORDER BY <oby_expression_list>)
I recommend to read following article as well:
String concatenation aggregation methods
New function VALIDATE_CONVERSION has been introduced in Oracle Database Release 12.2.It determines wether a given expression can be converted to the requested data type. It can return:
- 1 – if conversion is possible or expression evaluates to NULL
- 0 – if conversion is not possible
- Error is expression returns error
CAST function in release 12.2 enables to add error handler DEFAULT return_value ON CONVERSION ERROR in case conversion fails.
New release 12.2 introduces possibility to generate long identifiers up to 128 characters for name like tables, views, triggers, columns and so on. In previous release it was limited to 30 characters.
This article presents installation of Oracle database 12C(12.1) on Fedora 25. Read following article to install Fedora 25 Linux: Install Fedora 25(for comfort set 4G memory for your virtual machine). Continue reading
This article presents how to install Fedora 25 – Live Workstation version.
I assume you have already downloaded Fedora 25 64 bit Live Workstation(about 1,3 G) and you know how to use VirtualBox 64 bit(100M). Create virtual machine with default settings for Linux Fedora 64 bit. 2GB ram and 64G(includes extra space for Oracle installations) for disk is enough plus increase video memory to 128M. Rest of options you can keep default.
Oracle Advanced Transparent Data Encryption (TDE) is used for encrypting sensitive data on storage data for Oracle database. The encryption is totally transparent for application. TDE was introduced in 10G enabling encryption of a columns in 11G it was enhanced with encryption for tablespaces.
This article describes new feature of 11g SecureFile LOB.
In new version 11g Oracle decided to create new type large objects (LOB) called Secure Files. It offers many new benefits versus old version of LOB called in 11g release BasicFile:
- intelligent compression
- transparent decryption
- easier management and development
If you want try to select CLOB column via database link then you get error ORA-22992
select * from <TABLE_NAME>@<DATABASE LINK>;
ORA-22992: cannot use LOB locators selected from remote tables
22992. 00000 - "cannot use LOB locators selected from remote tables"
*Cause: A remote LOB column cannot be referenced.
*Action: Remove references to LOBs in remote tables.
This article shows how to avoid this error