Semantics |
Informix |
Oracle |
Logical logs |
Redo logs |
Physical log |
Rollback segment
Undo |
chunk |
datafile |
dbspace or dbslice |
tablespace |
rootdbs |
system tablespace |
extent |
extent |
blob |
blob |
Shared Memory |
SGA |
BEGIN WORK
MODE ANSI |
Always in the equivalent of MODE ANSI |
SysMaster |
Catalog
Data Dictionary |
INTO TEMP Clause |
CREATE TABLE <table_name> AS
SELECT ... |
Fragment |
Partition |
Now Rowid In Fragment Table |
All Rows Have A Rowid |
Numeric Rowid |
Non Numeric Rowid |
Index Maps Rowid To A Physical Location |
Rowid Is A Physical Location |
Disk Page |
Block |
Locks |
Blocks (Disk Page) Not Lockable
Indexes Not Lockable |
DATABASE <database_name> EXCLUSIVE |
STARTUP RESTRICT |
Set Transaction Read Uncommited |
Dirty Read Is Impossible |
Extended Data Types |
Types |
Serial Data Type |
Sequence ... but an independent object
identical to DB2 implementation |
CHAR datatype 32K |
Char datatype 4K |
NUMBER (up to 32 digits) |
NUMBER (up to 38 digits) |
Boolean True/False have literal
representation |
Booleans have no literal representation |
VARCHAR datatype 255 bytes |
VARCHAR2 datatype 4K |
CLOB |
CLOB up to 4GB |
CLOB not stored in the row |
CLOB stored in or out of row |
USER |
USER |
CURRENT |
SYSDATE |
DB_LOCALE |
Character Set
National Character Set |
Logging:
No Logging
Unbuffered Logging
Buffered Logging |
Logging:
Not possible
Not possible
Oracle |
Round Robin |
Hash Partition |
Fragment By Expression |
Range Partition |
The three levels of database privilege
(Connect, Resource, and DBA) provide an overall means of controlling who accesses a
database. |
No equivalent ... these are sample roles |
Table Level Privileges:
Select
Insert
Delete
Update |
Table Level Privileges:
Select
Insert
Delete
Update
Reference
|
Execute Privilege |
Execute Privilege |
Roles |
Roles - similar functionality |
View can not contain UNION or ORDER BY |
Any SQL Statement Allowed |
View no modification if > 1 table |
Modify anything if key preserved |
Triggers Before & After |
Available, but must be separate triggers |
Triggers Statement * Row Level Mixed |
Statement & Row Level Separate |
Table triggers only |
|
ORDER BY in View not possible |
ORDER BY in Views |
ONBAR and ONTAPE |
RMAN |
No lock escalation |
No lock escalation |
DECODE |
DECODE |
UNIQUE |
UNIQUE |