XXII. DB++ Functions

Warning

This extension is EXPERIMENTAL. The behaviour of this extension -- including the names of its functions and anything else documented about this extension -- may change without notice in a future release of PHP. Use this extension at your own risk.

Introduction

db++, made by the German company Concept asa, is a relational database system with high performance and low memory and disk usage in mind. While providing SQL as an additional language interface, it is not really a SQL database in the first place but provides its own AQL query language which is much more influenced by the relational algebra than SQL is.

Concept asa always had an interest in supporting open source languages, db++ has had Perl and Tcl call interfaces for years now and uses Tcl as its internal stored procedure language.

Requirements

This extension relies on external client libraries so you have to have a db++ client installed on the system you want to use this extension on.

Concept asa provides db++ Demo versions and documentation for Linux, some other Unix versions. There is also a Windows version of db++, but this extension doesn't support it (yet).

Installation

In order to build this extension yourself you need the db++ client libraries and header files to be installed on your system (these are included in the db++ installation archives by default). You have to run configure with option --with-dbplus to build this extension.

configure looks for the client libraries and header files under the default paths /usr/dbplus, /usr/local/dbplus and /opt/dblus. If you have installed db++ in a different place you have add the installation path to the configure option like this: --with-dbplus=/your/installation/path.

Runtime Configuration

This extension has no configuration directives defined in php.ini.

Resource Types

dbplus_relation

Most db++ functions operate on or return dbplus_relation resources. A dbplus_relation is a handle to a stored relation or a relation generated as the result of a query.

Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

db++ error codes

Table 1. DB++ Error Codes

PHP Constant	db++ constant	meaning
`DBPLUS_ERR_NOERR` (integer)	ERR_NOERR	Null error condition
`DBPLUS_ERR_DUPLICATE` (integer)	ERR_DUPLICATE	Tried to insert a duplicate tuple
`DBPLUS_ERR_EOSCAN` (integer)	ERR_EOSCAN	End of scan from rget()
`DBPLUS_ERR_EMPTY` (integer)	ERR_EMPTY	Relation is empty (server)
`DBPLUS_ERR_CLOSE` (integer)	ERR_CLOSE	The server can't close
`DBPLUS_ERR_WLOCKED` (integer)	ERR_WLOCKED	The record is write locked
`DBPLUS_ERR_LOCKED` (integer)	ERR_LOCKED	Relation was already locked
`DBPLUS_ERR_NOLOCK` (integer)	ERR_NOLOCK	Relation cannot be locked
`DBPLUS_ERR_READ` (integer)	ERR_READ	Read error on relation
`DBPLUS_ERR_WRITE` (integer)	ERR_WRITE	Write error on relation
`DBPLUS_ERR_CREATE` (integer)	ERR_CREATE	Create() system call failed
`DBPLUS_ERR_LSEEK` (integer)	ERR_LSEEK	Lseek() system call failed
`DBPLUS_ERR_LENGTH` (integer)	ERR_LENGTH	Tuple exceeds maximum length
`DBPLUS_ERR_OPEN` (integer)	ERR_OPEN	Open() system call failed
`DBPLUS_ERR_WOPEN` (integer)	ERR_WOPEN	Relation already opened for writing
`DBPLUS_ERR_MAGIC` (integer)	ERR_MAGIC	File is not a relation
`DBPLUS_ERR_VERSION` (integer)	ERR_VERSION	File is a very old relation
`DBPLUS_ERR_PGSIZE` (integer)	ERR_PGSIZE	Relation uses a different page size
`DBPLUS_ERR_CRC` (integer)	ERR_CRC	Invalid crc in the superpage
`DBPLUS_ERR_PIPE` (integer)	ERR_PIPE	Piped relation requires lseek()
`DBPLUS_ERR_NIDX` (integer)	ERR_NIDX	Too many secondary indices
`DBPLUS_ERR_MALLOC` (integer)	ERR_MALLOC	Malloc() call failed
`DBPLUS_ERR_NUSERS` (integer)	ERR_NUSERS	Error use of max users
`DBPLUS_ERR_PREEXIT` (integer)	ERR_PREEXIT	Caused by invalid usage
`DBPLUS_ERR_ONTRAP` (integer)	ERR_ONTRAP	Caused by a signal
`DBPLUS_ERR_PREPROC` (integer)	ERR_PREPROC	Error in the preprocessor
`DBPLUS_ERR_DBPARSE` (integer)	ERR_DBPARSE	Error in the parser
`DBPLUS_ERR_DBRUNERR` (integer)	ERR_DBRUNERR	Run error in db
`DBPLUS_ERR_DBPREEXIT` (integer)	ERR_DBPREEXIT	Exit condition caused by prexit() * procedure
`DBPLUS_ERR_WAIT` (integer)	ERR_WAIT	Wait a little (Simple only)
`DBPLUS_ERR_CORRUPT_TUPLE` (integer)	ERR_CORRUPT_TUPLE	A client sent a corrupt tuple
`DBPLUS_ERR_WARNING0` (integer)	ERR_WARNING0	The Simple routines encountered a non fatal error which was corrected
`DBPLUS_ERR_PANIC` (integer)	ERR_PANIC	The server should not really die but after a disaster send ERR_PANIC to all its clients
`DBPLUS_ERR_FIFO` (integer)	ERR_FIFO	Can't create a fifo
`DBPLUS_ERR_PERM` (integer)	ERR_PERM	Permission denied
`DBPLUS_ERR_TCL` (integer)	ERR_TCL	TCL_error
`DBPLUS_ERR_RESTRICTED` (integer)	ERR_RESTRICTED	Only two users
`DBPLUS_ERR_USER` (integer)	ERR_USER	An error in the use of the library by an application programmer
`DBPLUS_ERR_UNKNOWN` (integer)	ERR_UNKNOWN

Table of Contents
dbplus_add -- Add a tuple to a relation
dbplus_aql -- Perform AQL query
dbplus_chdir -- Get/Set database virtual current directory
dbplus_close -- Close a relation
dbplus_curr -- Get current tuple from relation
dbplus_errcode -- Get error string for given errorcode or last error
dbplus_errno -- Get error code for last operation
dbplus_find -- Set a constraint on a relation
dbplus_first -- Get first tuple from relation
dbplus_flush -- Flush all changes made on a relation
dbplus_freealllocks -- Free all locks held by this client
dbplus_freelock -- Release write lock on tuple
dbplus_freerlocks -- Free all tuple locks on given relation
dbplus_getlock -- Get a write lock on a tuple
dbplus_getunique -- Get an id number unique to a relation
dbplus_info -- Get information about a relation
dbplus_last -- Get last tuple from relation
dbplus_lockrel -- Request write lock on relation
dbplus_next -- Get next tuple from relation
dbplus_open -- Open relation file
dbplus_prev -- Get previous tuple from relation
dbplus_rchperm -- Change relation permissions
dbplus_rcreate -- Creates a new DB++ relation
dbplus_rcrtexact -- Creates an exact but empty copy of a relation including indices
dbplus_rcrtlike -- Creates an empty copy of a relation with default indices
dbplus_resolve -- Resolve host information for relation
dbplus_restorepos -- Restore position
dbplus_rkeys -- Specify new primary key for a relation
dbplus_ropen -- Open relation file local
dbplus_rquery -- Perform local (raw) AQL query
dbplus_rrename -- Rename a relation
dbplus_rsecindex -- Create a new secondary index for a relation
dbplus_runlink -- Remove relation from filesystem
dbplus_rzap -- Remove all tuples from relation
dbplus_savepos -- Save position
dbplus_setindex -- Set index
dbplus_setindexbynumber -- Set index by number
dbplus_sql -- Perform SQL query
dbplus_tcl -- Execute TCL code on server side
dbplus_tremove -- Remove tuple and return new current tuple
dbplus_undo -- Undo
dbplus_undoprepare -- Prepare undo
dbplus_unlockrel -- Give up write lock on relation
dbplus_unselect -- Remove a constraint from relation
dbplus_update -- Update specified tuple in relation
dbplus_xlockrel -- Request exclusive lock on relation
dbplus_xunlockrel -- Free exclusive lock on relation