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A database must have a database dictionary; this file has the database name with extension .fdd. It is created with CTDatabase::CreateDatabase(), 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 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:
