This article presents how to install Oracle 18C on Oracle Enterprise Linux 7 (OEL7) in silent mode.
Install Oracle Database 18C in silent mode on OEL7
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Qualified expressions for PL/SQL Oracle Database 18C
In Oracle Database 18C type initialization is simplified with qualified expressions for Record type and Associative Array Type. It can help simplify coding.
Record
rec_var := (field_name => some_value, .., field_name => some_value)
Associative Array
rec_var := (1 => some_value, .., 10 => some_value)
Private Temporary Tables Oracle Database 18C
New type of temporary tables appeared in 18C called Private Temporary Tables. They are temporary database objects that are dropped at the end of a transaction or session. Private temporary tables are stored in memory and each one is visible only to the session that created it.
CREATE PRIVATE TEMPORARY TABLE .... ON COMMIT DROP DEFINITION or CREATE PRIVATE TEMPORARY TABLE .... ON COMMIT PRESERVE DEFINITION
DROP DEFINITION |
This creates a private temporary table that is transaction specific. All data in the table is lost, and the table is dropped at the end of transaction. |
PRESERVE DEFINITION |
This creates a private temporary table that is session specific. All data in the table is lost, and the table is dropped at the end of the session that created the table. |
Schema Only Accounts Oracle Database 18C
New type of schema can be created in 18C where user has no password.
CREATE USER username NO AUTHENTICATION;
Scalable sequences Oracle Database 18C
Sequence is commonly known oracle object that is used to generate numbers in specified orders. In Oracle 18C new extra words can be defined for sequence creation:
- SCALE | NOSCALE(default)
- EXTEND | NOEXTEND(default)
Cancel SQL statement Oracle Database 18C
In latest version of database 18C instead of killing user session you can cancel its currently running or opened SQL statement using the ALTER SYSTEM CANCEL SQL statement. Continue reading
sqlplus catch and log all ORA- errors
Following article shows how to catch all ORA- statements in sqlplus using clause
SET ERRORLOGGING ON
Indexing NULL for Oracle
General rule for creating indexes in Oracle is following:
- Bitmap indexes – always index nulls
- B*Tree cluster indexes – always indexes nulls
- B*Tree indexes – can’t index data if all indexed columns are NULL
The last one can cause some performance issues but there is trick to index all NULL columns also for B*Tree indexes.
Install Oracle 18C on Oracle Linux 7 (OEL7)
This article presents how to install Oracle 18C on Oracle Enterprise Linux 7 (OEL7).
Read following article how to install Oracle Enterprise Linux 7: Install Oracle Linux 7 (OEL7) (set 8G memory for your virtual machine before proceeding with Oracle software installation).
Code Based Access Control for Definer’s Rights and Invoker’s Rights Oracle Database 12C release 2 (12.2)
In Oracle 12C it’s possible to assign a role to a code procedure/function/package
GRANT role_name TO PROCEDURE|FUNCTION|PACKAGE code_name;
This kind of grant can be executed only by following user:
- SYS
- user with GRANT ANY ROLE privilege
- user who own code and was granted the role with ADMIN OPTION
- user who own code and was granted the role with DELEGATE OPTION
Top three options are commonly know. New option is DELEGATE OPTION. It enables to grant a role to procedure|function|package and nothing more.
Once the role is granted to a code the role is always enabled no matter if the code is created with PRAGMA AUTHID_USER or PRAGMA DEFINER and no matter if owner of the code calls it or other user.