User Guide

SAP AG November 2002
_MAXEVENTS ................................................................................................................. 89
_MAX_MESSAGE_FILES................................................................................................ 89
_ROW_RGNS .................................................................................................................. 90
_TAB_RGNS .................................................................................................................... 90
_TRANS_RGNS............................................................................................................... 90
_TREE_RGNS.................................................................................................................. 90
_UNICODE....................................................................................................................... 90
SAP DB as UNICODE Database ......................................................................................... 90
UNICODE......................................................................................................................... 91
Installing a UNICODE-Enabled Database........................................................................ 91
Setting Database Parameter _UNICODE..................................................................... 92
Setting Code Attribute UNICODE................................................................................. 92
UNICODE and SQL.......................................................................................................... 93
Example 1..................................................................................................................... 94
UNICODE in Programming Languages ........................................................................... 96
Example 2..................................................................................................................... 97
Data Management Using B* Trees .................................................................................... 101
Concepts ........................................................................................................................ 101
Primary Key ................................................................................................................ 101
Secondary Key ........................................................................................................... 102
B* Tree........................................................................................................................ 102
Root/Index Page ..................................................................................................... 103
Leaf Page................................................................................................................ 103
Table Access........................................................................................................... 103
Table ID ...................................................................................................................... 104
B* Trees for Tables ........................................................................................................ 104
B* Trees for Table with LONG Columns..................................................................... 104
B* Trees for Tables with Secondary Key.................................................................... 105
B* Trees for Tables with LONG Columns and Secondary Key .................................. 106
Table Access Using B* Tree .......................................................................................... 107
Table Access (SELECT) Using B* Tree ..................................................................... 107
Table Access (INSERT) Using B* Tree ...................................................................... 109
Table Access (DELETE) Using B* Tree ..................................................................... 110
Table Access (UPDATE) Using B* Tree..................................................................... 111
Changes in the B* Tree Structure .................................................................................. 111
Non-Uniform Distributions of Data Pages................................................................... 112
Lock Behavior .................................................................................................................... 113
Lock ................................................................................................................................ 113
Shared Lock................................................................................................................ 114
Exclusive Lock ............................................................................................................ 115
User Manual: SAP DB 9