Overview
The information used by Pervasive PSQL and its components is stored in special tables called system tables.
*Caution: Do not attempt to modify system tables with DELETE, UPDATE, or INSERT statements, or user-defined triggers. System tables should never be altered directly.
Do not write your applications to query system tables directly. Some columns in system tables may not be documented. Your application can retrieve information stored in system tables by using any of the following methods:
•
System Stored Procedures
•
Transact-SQL statements and functions
•
Functions provided in the Pervasive PSQL application programming interfaces (API)
Note that the Pervasive PSQL APIs are documented in the Pervasive PSQL Developer Reference. The development components are compatible with the database engine from release to release. The format of the system tables depends on the internal architecture of the Pervasive PSQL database engine. The architecture may change from release to release. Application that directly access undocumented columns of system tables may have to be changed if the internal architecture of Pervasive PSQL changes.
For each system table, the following table indicates the name of the associated file and briefly describes the system table’s contents.
*Note: Some data in the system tables cannot be displayed. User passwords, for example, display in encrypted form.
 
Table 144
System Tables 
System Table
Dictionary File
Contents
V11
V22
X$Attrib
ATTRIB.DDF
PVATTRIB.DDF
Column attributes definitions.
X$Depend
DEPEND.DDF
PVDEPEND.DDF
Trigger dependencies such as tables, views, and procedures.
X$Field
FIELD.DDF
PVFIELD.DDF
Column and named index definitions.
X$File
FILE.DDF
PVFILE.DDF
Names and locations of the tables in your database.
X$Index
INDEX.DDF
PVINDEX.DDF
Index definitions.
X$Proc
PROC.DDF
PVPROC.DDF
Stored procedure definitions.
X$Relate
RELATE.DDF
PVRELATE.DDF
Referential integrity (RI) information.
X$Rights
RIGHTS.DDF
PVRIGHTS.DDF
User and group access rights definitions.
X$Trigger
TRIGGER.DDF
PVTRIG.DDF
Trigger information.
X$User
USER.DDF
PVUSER.DDF
User names, group names, and passwords.
X$View
VIEW.DDF
PVVIEW.DDF
View definitions.
1Applies to version 1 (V1) metadata. See Versions of Metadata.
2Applies to version 2 (V2) metadata. See Versions of Metadata.
Pervasive PSQL creates all of the system tables when you create a database.
Two other system tables that you may encounter are VARIANT.DDF and OCCURS.DDF (for a V1 database) and PVVARIANT.DDF and PVOCCURS.DDF (for a V2 database).These two system files are used for COBOL support and do not require any direct intervention by a user. Future versions of the utilities for COBOL may implement a different architecture, in which case these system tables may no longer be required. See also SQL Access for COBOL Applications.