XXI. DB++ Functions


本扩展模块是实验性的。该模块的行为,包括其函数的名称以及其它任何关于此模块的文档可能会在没有通知的情况下随 PHP 以后的发布而改变。我们提醒您在使用本扩展模块的同时自担风险。


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 then 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.


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).


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.





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.


由于这些常量是由该扩展模块定义的,因此只有在该扩展模块被编译到 PHP 中,或者在运行时被动态加载后,这些常量才有效。

db++ error codes

表格 1. DB++ Error Codes

PHP Constantdb++ constantmeaning
DBPLUS_ERR_NOERR (integer) ERR_NOERRNull error condition
DBPLUS_ERR_DUPLICATE (integer) ERR_DUPLICATETried to insert a duplicate tuple
DBPLUS_ERR_EOSCAN (integer) ERR_EOSCANEnd of scan from rget()
DBPLUS_ERR_EMPTY (integer) ERR_EMPTYRelation is empty (server)
DBPLUS_ERR_CLOSE (integer) ERR_CLOSEThe server can't close
DBPLUS_ERR_WLOCKED (integer) ERR_WLOCKEDThe record is write locked
DBPLUS_ERR_LOCKED (integer) ERR_LOCKEDRelation was already locked
DBPLUS_ERR_NOLOCK (integer) ERR_NOLOCKRelation cannot be locked
DBPLUS_ERR_READ (integer) ERR_READRead error on relation
DBPLUS_ERR_WRITE (integer) ERR_WRITEWrite error on relation
DBPLUS_ERR_CREATE (integer) ERR_CREATECreate() system call failed
DBPLUS_ERR_LSEEK (integer) ERR_LSEEKLseek() system call failed
DBPLUS_ERR_LENGTH (integer) ERR_LENGTHTuple exceeds maximum length
DBPLUS_ERR_OPEN (integer) ERR_OPENOpen() system call failed
DBPLUS_ERR_WOPEN (integer) ERR_WOPENRelation already opened for writing
DBPLUS_ERR_MAGIC (integer) ERR_MAGICFile is not a relation
DBPLUS_ERR_VERSION (integer) ERR_VERSIONFile is a very old relation
DBPLUS_ERR_PGSIZE (integer) ERR_PGSIZERelation uses a different page size
DBPLUS_ERR_CRC (integer) ERR_CRCInvalid crc in the superpage
DBPLUS_ERR_PIPE (integer) ERR_PIPEPiped relation requires lseek()
DBPLUS_ERR_NIDX (integer) ERR_NIDXToo many secondary indices
DBPLUS_ERR_MALLOC (integer) ERR_MALLOCMalloc() call failed
DBPLUS_ERR_NUSERS (integer) ERR_NUSERSError use of max users
DBPLUS_ERR_PREEXIT (integer) ERR_PREEXITCaused by invalid usage
DBPLUS_ERR_ONTRAP (integer) ERR_ONTRAPCaused by a signal
DBPLUS_ERR_PREPROC (integer) ERR_PREPROCError in the preprocessor
DBPLUS_ERR_DBPARSE (integer) ERR_DBPARSEError in the parser
DBPLUS_ERR_DBPREEXIT (integer) ERR_DBPREEXITExit condition caused by prexit() * procedure
DBPLUS_ERR_WAIT (integer) ERR_WAITWait a little (Simple only)
DBPLUS_ERR_CORRUPT_TUPLE (integer) ERR_CORRUPT_TUPLEA 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_FIFOCan't create a fifo
DBPLUS_ERR_PERM (integer) ERR_PERMPermission denied
DBPLUS_ERR_USER (integer) ERR_USER An error in the use of the library by an application programmer

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 -- ???
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 -- ???
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 -- ???
dbplus_setindex -- ???
dbplus_setindexbynumber -- ???
dbplus_sql -- Perform SQL query
dbplus_tcl -- Execute TCL code on server side
dbplus_tremove -- Remove tuple and return new current tuple
dbplus_undo -- ???
dbplus_undoprepare -- ???
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

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