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DBINFO()
Return and optionally change information about a database file opened in a
work area
------------------------------------------------------------------------------
Syntax
DBINFO(<nInfoType>, [<expNewSetting>])
--> uCurrentSetting
Arguments
<nInfoType> determines the type of information, as specified by the
constants below. Note, however, that not all constants are supported
for all RDDs. These constants are defined in the Dbinfo.ch header file,
which must be included (#include) in your application.
File Information Type Constants
------------------------------------------------------------------------
Constant Description
------------------------------------------------------------------------
DBI_ALIAS Alias name of the work area as a string.
DBI_BLOB_DIRECT_LEN Returns the storage length of a data item in a
BLOB file. <expNewSetting> must specify a
valid BLOB pointer obtained from
DbFieldInfo(DBS_BLOB_POINTER, <nFieldpos>),
BLOBDirectPut() or BLOBDirectImport().
DBI_BLOB_DIRECT_TYPE Returns the data type of a data item in a BLOB
file. <expNewSetting> must specify a valid BLOB
pointer obtained from
DbFieldInfo (DBS_BLOB_POINTER, <nFieldpos>),
BLOBDirectPut(), or BLOBDirectImport().
DBI_BLOB_INTEGRITY Tests a BLOB file for the integrity of its
internal tables and returns a logical value
indicating the success, true (.T.) or failure,
false (.F.) of the integrity check. If the
integrity check fails, you can run
dbInfo(DBI_BLOB_RECOVER) which will
automatically correct the BLOB file's tables.
Checking a BLOB file's integrity is a disk
intensive operation and should only be
performed when the file's integrity is in
question.
DBI_BLOB_OFFSET Returns the file offset of a data item in a
BLOB file. <expNewSetting> must specify a valid
BLOB pointer obtained from
DbFieldInfo(DBS_BLOB_POINTER, <nFieldpos>),
BLOBDirectPut(), or BLOBDirectImport().
DBI_BLOB_RECOVER Recovers a damaged BLOB file by correcting its
internal tables. You should run this function
only is dbInfo(DBI_BLOB_INTEGRITY) returns
false (.F.). Note that this function can only
correct the BLOB file's internal tables, it
cannot restore any data that may have become
corrupted.
DBI_BOF Logical value indicating the work area's
beginning of file status (see BOF()).
DBI_CANPUTREC Logical value indicating whether the work area
supports putting records.
DBI_CHILDCOUNT Number of relations set from this work area.
DBI_DB_VERSION String containing version information of the
host RDD. If the optional <expNewSetting>
parameter is provided, and it is one (1), the
result is a more detailed version of the
version being returned.
DBI_DBFILTER Filter expression as a string (see DBFILTER()).
DBI_EOF Logical value indicating the work area's end of
file status (see EOF()).
DBI_FCOUNT Number of fields (see FCOUNT()).
DBI_FILEHANDLE Integer representing the DOS file handle for
this database file.
DBI_FOUND Logical value indicating the success or failure
of the last seek operation in the work area
(see FOUND()).
DBI_FCOUNT Number of fields (see FCOUNT()).
DBI_FULLPATH Returns the full path name of the opened
database file.
DBI_GETDELIMITER Default delimiter.
DBI_GETHEADERSIZE Header size of the file (see HEADER()).
DBI_GETLOCKARRAY Array of locked records.
DBI_GETRECSIZE Record size of the file (see RECSIZE()).
DBI_ISDBF Logical value indicating whether the RDD
provides support for the .dbf file format.
DBI_ISFLOCK File lock status.
DBI_LASTUPDATE Last date on which the file was updated (see
LUPDATE()).
DBI_LOCKCOUNT Number of locked records.
DBI_LOCKOFFSET Current locking offset as a numeric value.
DBI_MEMOBLOCKSIZE Block size for the memo file associated with
this database.
DBI_MEMOEXT Default extension for the memo file associated
with this database.
DBI_MEMOHANDLE Integer representing the DOS file handle for
the memo file associated with this database
file.
DBI_RDD_VERSION String containing version information of the
RDD for this database. If the optional
<expNewSetting> parameter is provided, and it
is one (1), the result is a more detailed
version of the version being returned.
DBI_SETDELIMITER Default delimiter.
DBI_SHARED Shared flag value.
DBI_TABLEEXT Database file extension.
DBI_VALIDBUFFER Logical value indicating whether the current
buffer is valid.
------------------------------------------------------------------------
Important! DBI_USER is a constant that returns the minimum value
that third-party RDD developers can use for defining new <nInfoType>
parameters. Values less than DBI_USER are reserved for Computer
Associates development.
<expNewSetting> is reserved for RDDs that allow the file information
to be changed, in addition to being retrieved. None of the RDDs
supplied with CA-Clipper support this argument. It can be omitted or
specified as NIL.
Returns
DBINFO() returns the current setting if <expNewSetting> is not
specified, . If <expNewSetting> is specified, the previous setting is
returned.
Description
DBINFO() retrieves information about a database file. By default, this
function operates on the currently selected work area. It can be made
to operate on an unselected work area by specifying it within an aliased
expression.
Examples
. The following examples return work area information:
#include Dbinfo.ch
? DBINFO(DBI_GETHEADERSIZE) // Same as HEADER()
? DBINFO(DBI_LASTUPDATE) // Same as LUPDATE()
? DBINFO(DBI_GETRECSIZE) // Same as RECSIZE()
? DBINFO(DBI_FILEHANDLE) // DOS file handle for
// the current database
// file
Files Library is CLIPPER.LIB, header file is Dbinfo.ch.
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