Versions of Metadata

The relational interface in Pervasive PSQL v10 supports two versions of metadata, referred to as version 1 (V1) and version 2 (V2).

Metadata version is a property of the database that you specify when you create a database. V1 metadata is the default. When you create a database, you must specify V2 metadata if you want that version.

Metadata version applies to all data dictionary files (DDFs) within that database. A single database cannot use some DDFs with V1 metadata and others with V2 metadata. DDFs from the two versions cannot interact.

The database engine can, however, concurrently access multiple databases and each database can use either V1 metadata or V2 metadata.

All databases created with Pervasive PSQL versions prior to Pervasive PSQL v10 use V1 metadata. Databases created with Pervasive PSQL v10 or later may use either metadata version depending on the database settings.

Comparison of Metadata Versions

Version 2 metadata allows for many identifier names to be up to 128 bytes long. Refer to Limits/Conditions of Pervasive PSQL Features for additional information. In addition, V2 metadata allows for permissions on views and stored procedures. See Permissions on Views and Stored Procedures .

The data dictionary files (DDFs) for V2 metadata are named differently than for V1. In many cases, the V2 DDFs contain additional fields and changes to existing fields. See System Tables .

Conversion Utility

Pervasive PSQL includes a conversion utility, pvmdconv, to convert V1 metadata to V2 metadata. See pvmdconv in Pervasive PSQL User's Guide.

Relational Interface Limits

The following table shows the limits or conditions that apply to features of the relational interface.

A Pervasive PSQL database may contain four billion objects in any valid combination. The objects are persisted in the data dictionary files.

See also Naming Conventions in Pervasive PSQL Programmer's Guide, which is part of the Pervasive PSQL Software Developer's Kit (SDK).

Table 2-1 Limits/Conditions of Pervasive PSQL Features
Pervasive PSQL Feature	Limit or Condition	Metadata
		V1	V2
Arguments in a parameter list for a stored procedure	300
CHAR column size	8,000 bytes1
Character string literal	A character in the string may be any ANSI character between 1 and 255 decimal.
Columns in a table	1,536
Columns allowed in a trigger or stored procedure	300
Column name2	20 bytes
Column name2	128 bytes
Column size	2 GB
Correlation name	limited by memory
Cursor name	18 bytes
Database name2	20 bytes
Database sessions	limited by memory
Data file path name	64 bytes (the maximum length of the data file path name is a combination of Xf$Loc path and the data file path)
Data file path name	250 bytes (the maximum length of the data file path name is a combination of Xf$Loc path and the data file path)
Function (user-defined) name2	30 bytes
Function (user-defined) name2	128 bytes
Group name2	30 bytes
Group name2	128 bytes
Index name2	20 bytes
Index name2	128 bytes
Key name2	20 bytes
Key name2	128 bytes
Label name	limited by memory
Number of ANDed predicates	300
Number of database objects	65,536
Number of database objects	2 billion
Parameter name	126 bytes
Password2	8 bytes
Password2	128 bytes
Procedure name2	30 bytes
Procedure name2	128 bytes
Referential integrity (RI) constraint name	20 bytes
Referential integrity (RI) constraint name	128 bytes
Representation of single quote	Two consecutive single quotes (``)
Result name	limited by memory
Savepoint name	limited by memory
SELECT list columns in a query	1,600
Size of a single term (quoted literal string) in an SQL statement	14,997, excluding null terminator and quotations (15,000 total)
SQL statement length	64 KB
SQL statements per session	limited by memory
Stored procedure size	64 KB
Table name2	20 bytes
Table name2	128 bytes
Table rows	2 billion
Joined tables per query	limited by memory
Trigger name2	20 bytes
Trigger name2	128 bytes
User name2	30 bytes
User name2	128 bytes
VARCHAR column size	8,000 bytes1
Variable name	limited by memory
View name2	20 bytes
View name2	128 bytes
1The maximum size of a CHAR or VARCHAR column that may be fully indexed is 255 bytes 2See also Identifier Restrictions by Identifier Type in Advanced Operations Guide.

Fully Qualified Object Names

A fully qualified object name combines the name of the database and the object using dot notation. For example, if you have a view named myview in database mydbase, the fully qualified object name is mydbase.myview.

Fully qualified object names need to be unique within a database. For example, suppose in database "mydbase," you name a table "acctpay" and a user-defined function (or any other object) "acctpay." The fully qualified name is "mydbase.acctpay," in which case Pervasive PSQL does not know to which object the name refers.