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A database must have a database dictionary; this file is named with the database name and an extension of .fdd. It is created with ctdbCreateDatabase(), and must exist for the user to connect to the database. Each database dictionary maintains information about the tables associated with the database. When a database is connected to the session, it is considered "active".
Database Dictionary Layout
Field |
Type |
Length |
Description |
|---|---|---|---|
TYPE |
CT_INT4 |
4 |
Record type: 1-database 2-table 3-index |
STATUS |
CT_INT4 |
4 |
Record status: 0-status ok 1-reserved |
LOGICAL_NAME |
CT_FSTRING |
128 |
Logical (database) name of database or table or index |
PHYSICAL_NAME |
CT_FSTRING |
128 |
Physical name of database or table or index |
LINK |
CT_FSTRING |
128 |
Name of table if record type is 3-index |
LINKNBR |
CT_INT4 |
4 |
Table UID if record type is 3-index |
PATH |
CT_FSTRING |
256 |
Path of database dictionary, data or index |
SUPEXT |
CT_FSTRING |
16 |
Super file extension (if super file is used) |
DATEXT |
CT_FSTRING |
16 |
Data file extension (usually .DAT) |
IDXEXT |
CT_FSTRING |
16 |
Index file extension (usually .IDX) |
VERSION |
CT_INT4 |
4 |
Record version: 0x00010000 (version 1.0) |
COUNTER |
CT_INT4 |
4 |
Deprecated. |
UID |
CT_INT4 |
4 |
UID for database or table or index |
OWNER |
CT_FSTRING |
128 |
Name of owner - used by the FairCom DB SQL server |
MIRROR_NAME |
CT_FSTRING |
128 |
Name of mirrored file. |
MIRROR_PATH |
CT_FSTRING |
128 |
Path of mirrored file. |
RESERVED |
CT_ARRAY |
3000 |
Reserved for future use |
This information is included for general information on the database dictionary structure. c-treeDB API has appropriate functions to retrieve any needed information from the database dictionary, such as the table UID or path.
A database dictionary file has several different record types:
