dbDatabase Class Reference

#include <database.h>

Inheritance diagram for dbDatabase:

Detailed Description

Database class.


Public Types
enum	dbAccessType { dbReadOnly, dbAllAccess, dbConcurrentRead, dbConcurrentUpdate }
enum	DetachFlags { COMMIT = 1, DESTROY_CONTEXT = 2 }
enum	dbLockType { dbSharedLock, dbExclusiveLock, dbCommitLock }
enum	dbErrorClass { NoError, QueryError, ArithmeticError, IndexOutOfRangeError, DatabaseOpenError, FileError, OutOfMemoryError, Deadlock, NullReferenceError, LockRevoked, FileLimitExeeded, InconsistentInverseReference, DatabaseReadOnly }
enum	dbThreadMode { dbNotUsePthreads, dbUsePthreads }
enum	dbReplicationMode { dbReplicated, dbStandalone }
typedef void(*	dbErrorHandler )(int error, char const msg, int msgarg, void context)
Public Member Functions
bool	open (char const databaseName, char const fileName=NULL, time_t waitLockTimeoutMsec=INFINITE, time_t commitDelaySec=0)
	Open database.
bool	open (OpenParameters &params)
	Open database with parameters defined in OpenParameters structure.
void	close ()
	Close database.
void	commit ()
	Commit transaction.
void	precommit ()
	Release all locks hold by transaction allowing other clients to proceed but do not flush changes to the disk.
void	rollback ()
	Rollback transaction.
void	scheduleBackup (char const *fileName, time_t periodSec)
	Schedule backup.
void	attach ()
	Attach current thread to the database.
void	attach (dbDatabaseThreadContext *ctx)
	Set transaction context for the current thread.
void	detach (int flags=COMMIT\|DESTROY_CONTEXT)
	Detach thread from the database.
void	lock (dbLockType lock=dbExclusiveLock)
	Exclusivly lock the database.
bool	backup (char const *file, bool compactify)
	Perform backup to the file with specified name.
bool	backup (dbFile *file, bool compactify)
	Perform backup to the specified file.
void	assign (dbTableDescriptor &desc)
	Assign table to the database.
void	setConcurrency (unsigned nThreads)
	Set concurrency level for sequential search and sort operations.
long	getAllocatedSize ()
	Get size allocated in the database since open.
long	getDatabaseSize ()
	Get size of the database file.
int	getNumberOfReaders ()
	Get number of threads accessing database in shared mode (readonly).
int	getNumberOfWriters ()
	Get number of threads accessing database in exclusiveh mode (for update).
int	getNumberOfBlockedReaders ()
	Get number of threads blocked while starting read-only transaction.
int	getNumberOfBlockedWriters ()
	Get number of threads blocked while starting update transaction.
int	getNumberOfUsers ()
	Get number of processes attached to the database.
void	allowColumnsDeletion (bool enabled=true)
	Enable deletion of columns from the table when correspondent fields are renamed from class descriptor.
bool	prepareQuery (dbAnyCursor *cursor, dbQuery &query)
	Prepare query.
dbErrorHandler	setErrorHandler (dbErrorHandler newHandler, void *errorHandlerContext=NULL)
	Set error handler.
virtual void	handleError (dbErrorClass error, char const *msg=NULL, int arg=0)
	Error handler.
void	insertRecord (dbTableDescriptor table, dbAnyReference ref, void const *record)
	Insert record in the database.
bool	isOpen () const
	Check if database is opened.
bool	isCommitted ()
	Check if current transaction is committed.
bool	isAttached ()
	Check if thread was attached to the database.
bool	isUpdateTransaction ()
	Check if current transaction is updating database.
int	getVersion ()
	Get database version.
void	setFileSizeLimit (size_t limit)
	Specify database file size limit.
template<class T>
dbReference< T >	insert (T const &record)
	Insert record in the database.
dbTableDescriptor *	lookupTable (dbTableDescriptor *desc)
	Find cloned table desciptor assigned to this database.
void	getMemoryStatistic (dbMemoryStatistic &stat)
	Get information about state of database memory.
void	setFixedSizeAllocator (size_t minSize, size_t maxSize, size_t quantum, size_t bufSize)
	Initialize fixed size allocator.
	dbDatabase (dbAccessType type=dbAllAccess, size_t dbInitSize=dbDefaultInitDatabaseSize, size_t dbExtensionQuantum=dbDefaultExtensionQuantum, size_t dbInitIndexSize=dbDefaultInitIndexSize, int nThreads=1)
	Database constructor.
virtual	~dbDatabase ()
	Database detructor.
Public Attributes
dbAccessType	accessType
size_t	initSize
size_t	extensionQuantum
size_t	initIndexSize
offs_t	freeSpaceReuseThreshold
Static Public Attributes
static char const *const	errorMessage []
Protected Member Functions
dbTableDescriptor *	loadMetaTable ()
	Loads all class descriptors.
void	cleanup (dbInitializationMutex::initializationStatus status, int step)
void	delayedCommit ()
void	backupScheduler ()
virtual bool	isReplicated ()
void	commit (dbDatabaseThreadContext *ctx)
	Commit transaction.
void	restoreTablesConsistency ()
	Restore consistency of table list of rows (last record should contain null reference in next field).
bool	isValidOid (oid_t oid)
	Check if OID corresponds to the valid object.
dbRecord *	getRow (oid_t oid)
	Get table row.
dbRecord *	putRow (oid_t oid, size_t newSize)
	Prepare for row insertion or update.
dbRecord *	putRow (oid_t oid)
	Prepare for object update ithout changing its size.
byte *	get (oid_t oid)
	Get record by OID.
byte *	put (oid_t oid)
	Prepare for update of internal object.
bool	isPrefixSearch (dbAnyCursor cursor, dbExprNode expr, dbExprNode andExpr, dbFieldDescriptor &indexedField)
	Check whether query is prefix search: "'key' like field+'%'".
bool	isIndexApplicable (dbAnyCursor cursor, dbExprNode expr, dbExprNode andExpr, dbFieldDescriptor &indexedField)
	Check whether search can be performed using indices.
bool	isIndexApplicable (dbAnyCursor cursor, dbExprNode expr, dbExprNode *andExpr)
	Check whether expression can be evaluated unsing index.
bool	followInverseReference (dbExprNode expr, dbExprNode andExpr, dbAnyCursor *cursor, oid_t iref)
	If query predicate contains operands from other tables (accessed by references) and inverse references exists, then FastDB performs indexed search in referenced table and then go back using inverse referenced to query table.
bool	existsInverseReference (dbExprNode *expr, int nExistsClauses)
	Check if there is inverse reference in the table rerefrenced from search predicate.
bool	evaluate (dbExprNode expr, oid_t oid, dbTable table, dbAnyCursor *cursor)
	Evaluate epression.
void	select (dbAnyCursor *cursor)
	Select all records from the table.
void	select (dbAnyCursor *cursor, dbQuery &query)
	Execute select query.
void	traverse (dbAnyCursor *cursor, dbQuery &query)
	Perform table traverse: execute queries with "start from (follow by)" clause.
void	update (oid_t oid, dbTableDescriptor table, void const record)
	Update record.
void	remove (dbTableDescriptor *table, oid_t oid)
	Remove record from the database.
offs_t	allocate (size_t size, oid_t oid=0)
	Allocate object in the database e.
void	deallocate (offs_t pos, size_t size)
	Deallocate region.
void	extend (offs_t size)
	Checks whther allocated size is greater than size of databae file and recreate memory mapping object with larger size n the last case.
void	cloneBitmap (offs_t pos, size_t size)
	Clone memory allocation bitmap for region [pos, pos+size).
oid_t	allocateId (int n=1)
	Allocate object identifier(s).
void	freeId (oid_t oid, int n=1)
	Free object identifier(s).
void	updateCursors (oid_t oid, bool removed=false)
	Update record in in all active cursors if it this record is checnged in the database.
void	recovery ()
	Perform database recovery after fault.
bool	checkVersion ()
	Check if program works with correct version of memory mapped object (if memory mapped object is reallocated by some client, its version number is incremented, so all other client will be able to notice it and also reallocate their memory mapping objects.
oid_t	allocateObject (dbInternalObject marker)
	Allocate internal object.
oid_t	allocateRow (oid_t tableId, size_t size)
	Allocate record.
void	allocateRow (oid_t tableId, oid_t oid, size_t size)
	Allocate record with specified OID.
void	freeRow (oid_t tableId, oid_t oid)
	Delete row from the table.
void	freeObject (oid_t oid)
	Free internal object.
bool	beginTransaction (dbLockType)
	Start database transaction.
void	endTransaction ()
	End transaction.
void	endTransaction (dbDatabaseThreadContext *ctx)
	End transaction with specified thread context.
virtual void	waitTransactionAcknowledgement ()
void	initializeMetaTable ()
	Initialize database metatable (table containning information about all other tables included metatable itself).
bool	loadScheme (bool alter)
	Load database scheme.
bool	completeDescriptorsInitialization ()
	This method is invoked by SubSQL to complete table descriptors initialization after loading of all table descriptoes from thr database.
void	reformatTable (oid_t tableId, dbTableDescriptor *desc)
	Reformat table according to new format.
bool	addIndices (bool alter, dbTableDescriptor *desc)
	Add new indices to the table.
oid_t	addNewTable (dbTableDescriptor *desc)
	Add new table to the database.
void	updateTableDescriptor (dbTableDescriptor *desc, oid_t tableId)
	Update database table descriptor.
void	insertInverseReference (dbFieldDescriptor *fd, oid_t reverseId, oid_t targetId)
	Insert inverse reference.
void	removeInverseReferences (dbTableDescriptor *desc, oid_t oid)
	Remove inverse references to the removed record.
void	removeInverseReference (dbFieldDescriptor *fd, oid_t reverseId, oid_t targetId)
	Remove inverse reference.
void	deleteTable (dbTableDescriptor *desc)
	Delete table from the database.
void	dropTable (dbTableDescriptor *desc)
	Delete all table records.
void	createIndex (dbFieldDescriptor *fd)
	Create T-Tree index for the field.
void	createHashTable (dbFieldDescriptor *fd)
	Create hash table for the field.
void	dropIndex (dbFieldDescriptor *fd)
	Drop T-Tree index for the field.
void	dropHashTable (dbFieldDescriptor *fd)
	Drop hash table for the field.
void	linkTable (dbTableDescriptor *table, oid_t tableId)
	Link table to the database table list.
void	unlinkTable (dbTableDescriptor *table)
	Unlink table from the database tables list.
bool	wasReserved (offs_t pos, size_t size)
	Check if location is reserved.
void	reserveLocation (dbLocation &location, offs_t pos, size_t size)
	Mark location as reserved.
void	commitLocation ()
	Remove location from list of reserved locations.
dbTableDescriptor *	findTable (char const *name)
	Find table using symbol name.
dbTableDescriptor *	findTableByName (char const *name)
	Find table by name.
dbTableDescriptor *	getTables ()
	Get list of tables attached to the database.
void	setDirty ()
	Mark database as been modified.
bool	isFree (offs_t pos, int objBitSize)
	Check if given location is free.
void	markAsAllocated (offs_t pos, int objBitSize)
	Set in memory allocation bitmap bits corresponding to the object.
Static Protected Member Functions
static void thread_proc	delayedCommitProc (void *arg)
static void thread_proc	backupSchedulerProc (void *arg)
static void _fastcall	execute (dbExprNode *expr, dbInheritedAttribute &iattr, dbSynthesizedAttribute &sattr)
	Execute expression.
static void	deleteCompiledQuery (dbExprNode *tree)
	Cleanup compiled query.
Protected Attributes
dbThreadPool	threadPool
FixedSizeAllocator	fixedSizeAllocator
dbThreadContext < dbDatabaseThreadContext >	threadContext
byte *	baseAddr
dbHeader *	header
offs_t *	currIndex
offs_t *	index [2]
unsigned	parThreads
bool	modified
size_t	currRBitmapPage
size_t	currRBitmapOffs
size_t	currPBitmapPage
size_t	currPBitmapOffs
dbLocation *	reservedChain
char *	databaseName
int	databaseNameLen
char *	fileName
int	version
size_t	committedIndexSize
size_t	currIndexSize
oid_t	updatedRecordId
unsigned	waitLockTimeout
size_t	fileSizeLimit
bool	uncommittedChanges
dbHashFunction	hashFunction
dbFile	file
dbSharedObject< dbMonitor >	shm
dbGlobalCriticalSection	cs
dbGlobalCriticalSection	mutatorCS
dbInitializationMutex	initMutex
dbSemaphore	writeSem
dbSemaphore	readSem
dbSemaphore	upgradeSem
dbEvent	backupCompletedEvent
dbMonitor *	monitor
dbTableDescriptor *	tables
int *	bitmapPageAvailableSpace
bool	opened
offs_t	allocatedSize
offs_t	deallocatedSize
time_t	commitDelay
time_t	commitTimeout
time_t	commitTimerStarted
dbMutex	delayedCommitStartTimerMutex
dbMutex	delayedCommitStopTimerMutex
dbLocalEvent	delayedCommitStartTimerEvent
dbEvent	delayedCommitStopTimerEvent
dbLocalEvent	commitThreadSyncEvent
bool	delayedCommitEventsOpened
dbMutex	backupMutex
dbLocalEvent	backupInitEvent
char *	backupFileName
time_t	backupPeriod
bool	stopDelayedCommitThread
dbThread	backupThread
dbThread	commitThread
int	accessCount
dbL2List	threadContextList
dbMutex	threadContextListMutex
dbErrorHandler	errorHandler
void *	errorHandlerContext
int	schemeVersion
dbVisitedObject *	visitedChain
bool	confirmDeleteColumns
int	maxClientId
int	selfId
unsigned	parallelScanThreshold
Static Protected Attributes
static size_t	internalObjectSize []
Friends
class	dbSelection
class	dbAnyCursor
class	dbHashTable
class	dbQuery
class	dbTtree
class	dbTtreeNode
class	dbRtree
class	dbRtreePage
class	dbParallelQueryContext
class	dbServer
class	dbColumnBinding
class	dbUserFunctionArgument
class	dbAnyContainer
class	dbFile
class	dbCLI
class	GiSTdb
class	dbHArray
Classes
struct	dbLocation
struct	OpenParameters
	Structure to specify database open parameters. More...

Member Typedef Documentation

typedef void(* dbErrorHandler)(int error, char const *msg, int msgarg, void *context)

Member Enumeration Documentation

enum dbAccessType

Enumerator:

dbReadOnly
dbAllAccess
dbConcurrentRead
dbConcurrentUpdate

enum DetachFlags

Enumerator:

COMMIT
DESTROY_CONTEXT

enum dbLockType

Enumerator:

dbSharedLock
dbExclusiveLock
dbCommitLock

enum dbErrorClass

Enumerator:

NoError
QueryError
ArithmeticError
IndexOutOfRangeError
DatabaseOpenError
FileError
OutOfMemoryError
Deadlock
NullReferenceError
LockRevoked
FileLimitExeeded
InconsistentInverseReference
DatabaseReadOnly

enum dbThreadMode

Enumerator:

dbNotUsePthreads
dbUsePthreads

enum dbReplicationMode

Enumerator:

dbReplicated
dbStandalone

Constructor & Destructor Documentation

dbDatabase	(	dbAccessType	type = `dbAllAccess`,
		size_t	dbInitSize = `dbDefaultInitDatabaseSize`,
		size_t	dbExtensionQuantum = `dbDefaultExtensionQuantum`,
		size_t	dbInitIndexSize = `dbDefaultInitIndexSize`,
		int	nThreads = `1`
	)

Database constructor.

Parameters:

	type	access type: `dbDatabase::dbReadOnly` or `dbDatabase::dbAllAcces`
	dbInitSize	initial size of the database. If FastDB is compiled with DISKLESS_CONFIGURATION option, then in this parameter MAXIMAL size of the database should be specified (in this mode database can not be reallocated)
	dbExtensionQuantum	quantum for extending memory allocation bitmap
	dbInitIndexSize	initial index size (objects)
	nThreads	concurrency level for sequential search and sort operations

See also:: setConcurrency(unsigned nThreads)

~dbDatabase ( ) [virtual]

Database detructor.

Member Function Documentation

bool open	(	char const *	databaseName,
		char const *	fileName = `NULL`,
		time_t	waitLockTimeoutMsec = `INFINITE`,
		time_t	commitDelaySec = `0`
	)

Open database.

Parameters:

	databaseName	database name
	fielName	path to the database file (if null, then file name daatbaseName + ".fdb" will be used)
	waitLockTimeoutMsec	timeout for waiting locks, by default disabled
	commitDelaySec	delayed commit timeout, by default disabled

Returns:: true if database was successfully opened

bool open ( OpenParameters & params )

Open database with parameters defined in OpenParameters structure.

Parameters:

params

parameters for openning database

Returns:: true if database was successfully opened

void close ( )

Close database.

void commit ( )

Commit transaction.

void precommit ( )

Release all locks hold by transaction allowing other clients to proceed but do not flush changes to the disk.

void rollback ( )

Rollback transaction.

void scheduleBackup	(	char const *	fileName,
		time_t	periodSec
	)

Schedule backup.

Parameters:

	fileName	path to backup file. If name ends with '?', then each backup willbe placed in seprate file with '?' replaced with current timestamp
	periodSec	preiod of performing backups in seconds

void attach ( )

Attach current thread to the database.

This method should be executed for all threads except one which opened the database.

void attach ( dbDatabaseThreadContext * ctx )

Set transaction context for the current thread.

Using this method allows to share the same transaction between different threads

Parameters:

ctx

transaction context which will be associated with the current thread

void detach ( int flags = COMMIT|DESTROY_CONTEXT )

Detach thread from the database.

Parameters:

flags

mask of DetachFlags COMMIT and DESTROY_CONTEXT

void lock ( dbLockType lock = dbExclusiveLock ) [inline]

Exclusivly lock the database.

bool backup	(	char const *	file,
		bool	compactify
	)

Perform backup to the file with specified name.

Parameters:

	file	path to the backup file
	comactify	if true then databae will be compactificated during backup - i.e. all used objects will be placed together without holes; if false then backup is performed by just writting memory mapped object to the backup file.

Returns:: whether backup was succeseful or not

bool backup	(	dbFile *	file,
		bool	compactify
	)

Perform backup to the specified file.

Parameters:

	file	opened file to path to the backup file. This file will not be closed after backup completion.
	comactify	if true then databae will be compactificated during backup - i.e. all used objects will be placed together without holes; if false then backup is performed by just writting memory mapped object to the backup file.

Returns:: whether backup was succeseful or not

void assign ( dbTableDescriptor & desc ) [inline]

Assign table to the database.

Parameters:

desc

table descriptor

void setConcurrency ( unsigned nThreads )

Set concurrency level for sequential search and sort operations.

By default, FastDB tries to detect number of CPUs in system and create the same number of threads.

Parameters:

nThreads

maximal number of threads to be created for perfroming cincurrent sequential search and sorting.

long getAllocatedSize ( ) [inline]

Get size allocated in the database since open.

Returns:: delta between size of allocated and deallocated data

long getDatabaseSize ( ) [inline]

Get size of the database file.

Returns:: database file size

int getNumberOfReaders ( ) [inline]

Get number of threads accessing database in shared mode (readonly).

Returns:: number of granted shared locks

int getNumberOfWriters ( ) [inline]

Get number of threads accessing database in exclusiveh mode (for update).

Returns:: number of granted exclusive locks (can be either 0 either 1)

int getNumberOfBlockedReaders ( ) [inline]

Get number of threads blocked while starting read-only transaction.

Returns:: number of threads which shared lock request was blocked

int getNumberOfBlockedWriters ( ) [inline]

Get number of threads blocked while starting update transaction.

Returns:: number of threads which exclusive lock request was blocked

int getNumberOfUsers ( ) [inline]

Get number of processes attached to the database.

Returns:: number of processes openned the database

void allowColumnsDeletion ( bool enabled = true ) [inline]

Enable deletion of columns from the table when correspondent fields are renamed from class descriptor.

By default it is switched of and database allows to delete fields only from empty table (to prevent unindented loose of data).

Parameters:

enabled

true to enable column deletion in non empty tables

bool prepareQuery	(	dbAnyCursor *	cursor,
		dbQuery &	query
	)

Prepare query.

This method can be used for explicit compilation of query and it's validation

Parameters:

	cursor	result set
	query	query expression

Returns:: true if query is successfully compiled, false othgerwise

dbDatabase::dbErrorHandler setErrorHandler	(	dbDatabase::dbErrorHandler	newHandler,
		void *	errorHandlerContext = `NULL`
	)

Set error handler.

Handler should be no-return function which perform stack unwind.

Parameters:

newHandler

new error handler

Returns:: previous handler

void handleError	(	dbErrorClass	error,
		char const *	msg = `NULL`,
		int	arg = `0`
	)			`[virtual]`

Error handler.

It can be redifined by application to implement application specific error handling.

Parameters:

	error	class of the error
	msg	error message
	arg	optional argument

Reimplemented in dbSubSql.

void insertRecord	(	dbTableDescriptor *	table,
		dbAnyReference *	ref,
		void const *	record
	)

Insert record in the database.

Parameters:

	table	table descriptor
	ref	[out] pointer to the references where ID of created object will be stored
	record	pointer to the transient object to be inserted in the table

bool isOpen ( ) const [inline]

Check if database is opened.

bool isCommitted ( )

Check if current transaction is committed.

Used mostly for debugging purposes.

bool isAttached ( )

Check if thread was attached to the database.

Used mostly for debugging purposes.

bool isUpdateTransaction ( )

Check if current transaction is updating database.

int getVersion ( )

Get database version.

void setFileSizeLimit ( size_t limit ) [inline]

Specify database file size limit.

Attempt to exeed this limit cause database error.

Parameters:

limit

maximal file size in bytes

dbReference<T> insert ( T const & record ) [inline]

Insert record in the database.

Parameters:

record

transient object to be insrted in the database

Returns:: reference to the created object

dbTableDescriptor * lookupTable ( dbTableDescriptor * desc )

Find cloned table desciptor assigned to this database.

Parameters:

des

static unassigned table descriptor

Returns:: clone of this table descriptor assigned to this databae or NULL if not found.

void getMemoryStatistic ( dbMemoryStatistic & stat )

Get information about state of database memory.

Parameters:

stat

placeholder for memory statistic

void setFixedSizeAllocator	(	size_t	minSize,
		size_t	maxSize,
		size_t	quantum,
		size_t	bufSize
	)			`[inline]`

Initialize fixed size allocator.

Parameters:

	minSize	minial object size allocated by this allocator
	maxSize	maximal object size allocated by this allocator
	quantum	difference in size between fixed size allocator chains
	bufSize	maximal number of free elements hold by this allocator

dbTableDescriptor * loadMetaTable ( ) [protected]

Loads all class descriptors.

This method should be used SubSQL and any other apllication which is should work with ANY database file.

Returns:: metatable descriptor

void cleanup	(	dbInitializationMutex::initializationStatus	status,
		int	step
	)			`[protected]`

void delayedCommit ( ) [protected]

void backupScheduler ( ) [protected]

static void thread_proc delayedCommitProc ( void * arg ) [inline, static, protected]

static void thread_proc backupSchedulerProc ( void * arg ) [inline, static, protected]

bool isReplicated ( ) [protected, virtual]

void commit ( dbDatabaseThreadContext * ctx ) [protected]

Commit transaction.

Parameters:

ctx

thread context

void restoreTablesConsistency ( ) [protected]

Restore consistency of table list of rows (last record should contain null reference in next field).

This method is used during recovery after crash and during rollback.

bool isValidOid ( oid_t oid ) [inline, protected]

Check if OID corresponds to the valid object.

Parameters:

oid

inspected OID

Returns:: whether OID is valid or not

Reimplemented in dbSubSql.

dbRecord* getRow ( oid_t oid ) [inline, protected]

Get table row.

Parameters:

oid

object indentifier

Returns:: object with this oid

dbRecord * putRow	(	oid_t	oid,
		size_t	newSize
	)			`[protected]`

Prepare for row insertion or update.

If record with such OID not exists or it is first time when it was changed during this transaction or size of recrod is changed, than new record is alocated in the database. Otherwisepointer to existed recordis returned.

Parameters:

	oid	object indetifier
	newSize	size of new object

Returns:: pointer inside database where object should should be stored

dbRecord* putRow ( oid_t oid ) [inline, protected]

Prepare for object update ithout changing its size.

Parameters:

oid

object indetifier

Returns:: pointer inside database where object should should be stored

byte* get ( oid_t oid ) [inline, protected]

Get record by OID.

Parameters:

oid

object identifier

Returns:: pointer to the record inside database

byte* put ( oid_t oid ) [inline, protected]

Prepare for update of internal object.

Parameters:

oid

internal object identifier

Returns:: pointer to the record inside database

bool isPrefixSearch	(	dbAnyCursor *	cursor,
		dbExprNode *	expr,
		dbExprNode *	andExpr,
		dbFieldDescriptor *&	indexedField
	)			`[protected]`

Check whether query is prefix search: "'key' like field+'%'".

Parameters:

	cursor	result set
	expr	evaluated expression
	andExpr	if not null, then it is used as filter to all records selected by index search
	indexedFile	[out] used to return information about which field was used to perfrom index search and so order in which selected records are sorted. If this order is the same as requested by "order by" clause, then no extra sorting is needed.

Returns:: true if search was performed using indeices, false if index is not applicable and sequential search is required

bool isIndexApplicable	(	dbAnyCursor *	cursor,
		dbExprNode *	expr,
		dbExprNode *	andExpr,
		dbFieldDescriptor *&	indexedField
	)			`[protected]`

Check whether search can be performed using indices.

Parameters:

	cursor	result set
	expr	evaluated expression
	andExpr	if not null, then it is used as filter to all records selected by index search
	indexedFile	[out] used to return information about which field was used to perfrom index search and so order in which selected records are sorted. If this order is the same as requested by "order by" clause, then no extra sorting is needed.

Returns:: true if search was performed using indeices, false if index is not applicable and sequential search is required

bool isIndexApplicable	(	dbAnyCursor *	cursor,
		dbExprNode *	expr,
		dbExprNode *	andExpr
	)			`[protected]`

Check whether expression can be evaluated unsing index.

If index is applicable, than index search is performed and result is stored in the cursor.

Parameters:

	cursor	result set
	expr	evaluated expression
	andExpr	if not null, then it is used as filter to all records selected by index search

Returns:: true if expression was evaluated using index, false if index is not applicable and sequential search is required

bool followInverseReference	(	dbExprNode *	expr,
		dbExprNode *	andExpr,
		dbAnyCursor *	cursor,
		oid_t	iref
	)			`[protected]`

If query predicate contains operands from other tables (accessed by references) and inverse references exists, then FastDB performs indexed search in referenced table and then go back using inverse referenced to query table.

followInverseReference method performs this backward traversal of inverse references.

Parameters:

	expr	evaluated expression
	andExpr	if not null, then it is used as filter to all records selected by index search
	cursor	cursor to collect selected records
	iref	OID of the selected records in referenced table

bool existsInverseReference	(	dbExprNode *	expr,
		int	nExistsClauses
	)			`[protected]`

Check if there is inverse reference in the table rerefrenced from search predicate.

Parameters:

	expr	evaluated expression
	nExistsClause	number of exists clauses in search wrapping this expression

Returns:: true if inverse reference(s) exists and it is possible to perform backward traversal

void _fastcall execute	(	dbExprNode *	expr,
		dbInheritedAttribute &	iattr,
		dbSynthesizedAttribute &	sattr
	)			`[static, protected]`

Execute expression.

This method is most frequently recursivly called during evaluation of search predicate.

Parameters:

	expr	expression to be executed
	iattr	inherited attributes - attributes passed top-down (information like cursor, current record, ...)
	sattr	synthesized attribute - sttributes passed down-top (value of expression)

bool evaluate	(	dbExprNode *	expr,
		oid_t	oid,
		dbTable *	table,
		dbAnyCursor *	cursor
	)			`[protected]`

Evaluate epression.

This method initialie initiainherited attributes and invoke execute method

Parameters:

	expr	expression to be evaluated
	oid	OID of the inspected record
	seaqched	table
	cursor	result set

Returns:: true if this record match search condition, false otherwise

void select ( dbAnyCursor * cursor ) [protected]

Select all records from the table.

Parameters:

cursor

result set

void select	(	dbAnyCursor *	cursor,
		dbQuery &	query
	)			`[protected]`

Execute select query.

Parameters:

	cursor	result set
	query	query expression

void traverse	(	dbAnyCursor *	cursor,
		dbQuery &	query
	)			`[protected]`

Perform table traverse: execute queries with "start from (follow by)" clause.

Parameters:

	cursor	result set
	query	query expression

void update	(	oid_t	oid,
		dbTableDescriptor *	table,
		void const *	record
	)			`[protected]`

Update record.

Parameters:

	oid	record identifier
	table	descriptor of the table to which record belongs
	record	updated image of the record

void remove	(	dbTableDescriptor *	table,
		oid_t	oid
	)			`[protected]`

Remove record from the database.

Parameters:

	table	descriptor of the table to which record belongs
	oid	record identifier

offs_t allocate	(	size_t	size,
		oid_t	oid = `0`
	)			`[protected]`

Allocate object in the database e.

Parameters:

	size	size of alocated object
	oid	if oid is not 0, then allocated region position is stored in correcpondent cell of object index (needed for allocation of bitmap pages)

Returns:: position of allcoated region

void deallocate	(	offs_t	pos,
		size_t	size
	)			`[protected]`

Deallocate region.

Parameters:

	pos	start position of region
	size	of region

void extend ( offs_t size ) [inline, protected]

Checks whther allocated size is greater than size of databae file and recreate memory mapping object with larger size n the last case.

Parameters:

size

allocated size

void cloneBitmap	(	offs_t	pos,
		size_t	size
	)			`[protected]`

Clone memory allocation bitmap for region [pos, pos+size).

Parameters:

	pos	start of region
	size	size of region

oid_t allocateId ( int n = 1 ) [protected]

Allocate object identifier(s).

Parameters:

number

of allocated object indentifiers

Returns:: object idenitifer (in case if n greater than 1, all n subsequent OIDs are allocated and first one is returned

void freeId	(	oid_t	oid,
		int	n = `1`
	)			`[protected]`

Free object identifier(s).

Parameters:

	oid	deallocated object identifer (or first of n deallocated subsequent identifiers if n greater than 1)
	number	of allocated object indentifiers

void updateCursors	(	oid_t	oid,
		bool	removed = `false`
	)			`[protected]`

Update record in in all active cursors if it this record is checnged in the database.

Parameters:

	oid	object indentifier of checnged record
	removed	true if record was removed

void recovery ( ) [protected]

Perform database recovery after fault.

Reimplemented in dbSubSql.

bool checkVersion ( ) [protected]

Check if program works with correct version of memory mapped object (if memory mapped object is reallocated by some client, its version number is incremented, so all other client will be able to notice it and also reallocate their memory mapping objects.

Returns:: true if memory mapping object was successfully reallocated or no reallocation is needed at all

oid_t allocateObject ( dbInternalObject marker ) [inline, protected]

Allocate internal object.

Parameters:

market

internal object tag

Returns:: oid of allocated object

oid_t allocateRow	(	oid_t	tableId,
		size_t	size
	)			`[inline, protected]`

Allocate record.

Parameters:

	tableId	object identifier of the table
	size	size of the created record as table descriptor in the database

void allocateRow	(	oid_t	tableId,
		oid_t	oid,
		size_t	size
	)			`[protected]`

Allocate record with specified OID.

Parameters:

	tableId	object identifier of the table
	oid	record OID
	size	size of the created record as table descriptor in the database

void freeRow	(	oid_t	tableId,
		oid_t	oid
	)			`[protected]`

Delete row from the table.

Parameters:

	tableId	OID of record with table descriptor
	oid	identifier of deleted record

void freeObject ( oid_t oid ) [protected]

Free internal object.

static void deleteCompiledQuery ( dbExprNode * tree ) [static, protected]

Cleanup compiled query.

bool beginTransaction ( dbLockType lockType ) [protected]

Start database transaction.

Parameters:

modify

if it is update or read-only rtansaction

Returns:: true if version of memory mapping object is not obsolete and reallocation is not possible

void endTransaction ( ) [inline, protected]

End transaction.

void endTransaction ( dbDatabaseThreadContext * ctx ) [protected]

End transaction with specified thread context.

Parameters:

ctx

thread context

void waitTransactionAcknowledgement ( ) [protected, virtual]

void initializeMetaTable ( ) [protected]

Initialize database metatable (table containning information about all other tables included metatable itself).

This method is invoked during database initialzation.

bool loadScheme ( bool alter ) [protected]

Load database scheme.

This method loads table decriptors from database, compare them with application classes, do necessary reformatting and save update andnew table decriptor in database

Parameters:

alter

if true then schema can be altered, otherwise there are some other active clients working with this database so schema can not be altered

bool completeDescriptorsInitialization ( ) [protected]

This method is invoked by SubSQL to complete table descriptors initialization after loading of all table descriptoes from thr database.

Returns:: true if intertable relation consuistency is rpeservedm false otherwise

void reformatTable	(	oid_t	tableId,
		dbTableDescriptor *	desc
	)			`[protected]`

Reformat table according to new format.

Parameters:

	tableId	OID of changed tables
	nw	table descriptor

bool addIndices	(	bool	alter,
		dbTableDescriptor *	desc
	)			`[protected]`

Add new indices to the table.

Parameters:

	alter	if true than indices can be added, otherwise there are some other active clients and adding new indices about which they will not know can lead to inconsistncy
	desc	new table descriptor

Returns:: true if indices were succesfully added

oid_t addNewTable ( dbTableDescriptor * desc ) [protected]

Add new table to the database.

Parameters:

desc

- descriptor of new table

Returns:: oid of created table descriptor record

void updateTableDescriptor	(	dbTableDescriptor *	desc,
		oid_t	tableId
	)			`[protected]`

Update database table descriptor.

Parameters:

	desc	application table descriptor
	tableId	OID of recrods with database table descriptor

void insertInverseReference	(	dbFieldDescriptor *	fd,
		oid_t	reverseId,
		oid_t	targetId
	)			`[protected]`

Insert inverse reference.

When reference or array of reference which is part of relation is updated then reference to the updated record is inserted in inverse reference field of all new referenced records (which were not referenced by this field before update).

Parameters:

	fd	descriptor of updated field (inverse reference should exist for this field)
	reverseId	OID of updated record
	targetId	OID of record referenced by this field

void removeInverseReferences	(	dbTableDescriptor *	desc,
		oid_t	oid
	)			`[protected]`

Remove inverse references to the removed record.

Parameters:

	desc	descriptor of table from which record is removed
	oid	OID of removed record

void removeInverseReference	(	dbFieldDescriptor *	fd,
		oid_t	reverseId,
		oid_t	targetId
	)			`[protected]`

Remove inverse reference.

When reference or array of reference which is part of relation is updated then reference to the updated record is removed from inverse reference field of all referenced records which are not reference any more from by this field.

Parameters:

	fd	descriptor of updated field (inverse reference should exist for this field)
	reverseId	OID of updated record
	targetId	OID of record referenced by this field

void deleteTable ( dbTableDescriptor * desc ) [protected]

Delete table from the database.

Parameters:

desc

table descriptor

void dropTable ( dbTableDescriptor * desc ) [protected]

Delete all table records.

Parameters:

desc

table descriptor

void createIndex ( dbFieldDescriptor * fd ) [protected]

Create T-Tree index for the field.

Parameters:

fd

field descriptor

void createHashTable ( dbFieldDescriptor * fd ) [protected]

Create hash table for the field.

Parameters:

fd

field descriptor

void dropIndex ( dbFieldDescriptor * fd ) [protected]

Drop T-Tree index for the field.

Parameters:

fd

field descriptor

void dropHashTable ( dbFieldDescriptor * fd ) [protected]

Drop hash table for the field.

Parameters:

fd

field descriptor

void linkTable	(	dbTableDescriptor *	table,
		oid_t	tableId
	)			`[protected]`

Link table to the database table list.

Parameters:

	table	table descriptor
	tableId	OID of record containing database table descriptor

void unlinkTable ( dbTableDescriptor * table ) [protected]

Unlink table from the database tables list.

Parameters:

table

table descriptor

bool wasReserved	(	offs_t	pos,
		size_t	size
	)			`[inline, protected]`

Check if location is reserved.

Parameters:

	pos	start position of the location
	size	location size

Returns:: true id location was reserved

void reserveLocation	(	dbLocation &	location,
		offs_t	pos,
		size_t	size
	)			`[inline, protected]`

Mark location as reserved.

This method is used by allocator to protect hole located in memory allocation bitmap, from been used by recursuve call of allocator (needed to clone bitmap pages).

Parameters:

	location	[out] local structure describing location.
	pos	start position of the location
	size	location size

void commitLocation ( ) [inline, protected]

Remove location from list of reserved locations.

It is done after location is marked as occupied in bitmap.

dbTableDescriptor * findTable ( char const * name ) [protected]

Find table using symbol name.

Parameters:

name

symbol table entry (returned by dbSymbolTable::add method)

Returns:: table descriptor or NULL if not found

dbTableDescriptor * findTableByName ( char const * name ) [protected]

Find table by name.

This method get symbol for specified name and call findTable method.

Parameters:

name

name of table

Returns:: table descriptor or NULL if not found

dbTableDescriptor* getTables ( ) [inline, protected]

Get list of tables attached to the database.

Returns:: list of tables attached to the database

void setDirty ( ) [protected]

Mark database as been modified.

bool isFree	(	offs_t	pos,
		int	objBitSize
	)			`[protected]`

Check if given location is free.

Parameters:

	pos	object offset
	objBitSize	object size i quantums

void markAsAllocated	(	offs_t	pos,
		int	objBitSize
	)			`[protected]`

Set in memory allocation bitmap bits corresponding to the object.

Parameters:

	pos	object offset
	objBitSize	object size i quantums

Friends And Related Function Documentation

friend class dbSelection [friend]

friend class dbAnyCursor [friend]

friend class dbHashTable [friend]

friend class dbQuery [friend]

friend class dbTtree [friend]

friend class dbTtreeNode [friend]

friend class dbRtree [friend]

friend class dbRtreePage [friend]

friend class dbParallelQueryContext [friend]

friend class dbServer [friend]

friend class dbColumnBinding [friend]

friend class dbUserFunctionArgument [friend]

friend class dbAnyContainer [friend]

friend class dbFile [friend]

friend class dbCLI [friend]

friend class GiSTdb [friend]

friend class dbHArray [friend]

Member Data Documentation

char const *const errorMessage [static]

Initial value:

{
    "No error",
    "Query syntax error",
    "Arithmetic exception",
    "Index out of range",
    "Database open error",
    "File access error",
    "Out of memory",
    "Deadlock",
    "Null reference",
    "Lock revoked",
    "File limit exeeded",
    "Inconsistent inverse reference",
    "Attempt to modify read-only database"
}

dbAccessType accessType

size_t initSize

size_t extensionQuantum

size_t initIndexSize

offs_t freeSpaceReuseThreshold

size_t internalObjectSize [static, protected]

Initial value:

 {
    0,
    dbPageSize,
    sizeof(dbTtree),
    sizeof(dbTtreeNode),
    sizeof(dbHashTable),
    sizeof(dbHashTableItem),
    sizeof(dbRtree),
    sizeof(dbRtreePage)
}