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Limit on number of open datasets in Delphi

Quote
>Is there a limit on the number of open and active datasets in Delphi and/or
>the component names for these datasets. Ie. are all the datasets stored in a
>stack and does that stack have a physical limit.

There are limits for different databases.
for BDE limits see http://www.inprise.com/devsupport/bde/ti_list/TI2751.html

--
Brian Bushay (TeamB)
Bbus...@NMPLS.com

 

Re:Limit on number of open datasets in Delphi


There are no limits in Delphi. There are limits in the BDE as follows.

Here are the maximum limits for some common BDE objects.

General BDE Limitations
48 Clients in system
32 Sessions per client (3.5 and earlier, 16 Bit, 32 Bit)
256 Session per client (4.0, 32 Bit)
32 Open databases per session (3.5 and earlier, 16 Bit, 32 Bit)
2048 Open databases per session (4.0, 32 Bit)
32 Loaded drivers
64 Sessions in system (3.5 and earlier, 16 Bit, 32 Bit)
12288 Sessions in system (4.0, 32 Bit)
4000 Cursors per session
16 Entries in error stack
8 Table types per driver
16 Field types per driver
8 Index types per driver
48K Size of configuration (IDAPI.CFG) file
64K Max size of SQL statement (RequestLive=False)
4K Max size of SQL statement (RequestLive=True)
6K Max size of SQL statement (RequestLive=True) (NEW BDE 4.01)
16K Record buffer size (SQL and ODBC)
31 Table and field name size in characters
64 Stored procedure name size in characters
16 Fields in key
3 File extension size in characters
260 Table name length in characters (some servers might have other
limits)
260 Path and file name length in characters

Paradox Limitations
127 Tables open per system
254 Tables open per system (NEW BDE 4.01)
64 Record locks on one table (16Bit) per session
255 Record locks on one table (32Bit) per session
255 Records in transactions on a table (32 Bit)
512 Open physical files (DB, PX, MB, X??, Y??, VAL, TV)
1024 Open physical files (DB, PX, MB, X??, Y??, VAL, TV) (NEW BDE 4.01)
300 Users in one PDOXUSRS.NET file
255 Number of fields per table
255 Size of character fields
2 Billion records in a table
2 Billion bytes in .DB (Table) file
10800 Bytes per record for indexed tables
32750 Bytes per record for non-indexed tables
127 Number of secondary indexes per table
16 Number of fields in an index
255 Concurrent users per table
256 Megabytes of data per BLOb field
100 Passwords per session
15 Password length
63 Passwords per table
159 Fields with validity checks (32 Bit)
63 Fields with validity checks (16 Bit)

dBASE Limitations
256 Open dBASE tables per system (16 Bit)
350 Open dBASE tables per system (BDE 3.0 - 4.0, 32 Bit)
512 Open dBASE tables per system (BDE 4.01, 32 Bit) (NEW BDE 4.01)
100 Record locks on one dBASE table (16 and 32 Bit)
100 Records in transactions on a dBASE table (32 Bit)
1 Billion records in a table
2 Billion bytes in .DBF (Table) file
4000 Size in bytes per record (dBASE 4)
32767 Size in bytes per record (dBASE for Windows)
255 Number of fields per table (dBASE 4)
1024 Number of fields per table (dBASE for Windows)
47 Number of index tags per .MDX file
254 Size of character fields
10 Open master indexes (.MDX) per table
220 Key expression length in characters

Bill

--

Bill Todd - TeamB
(TeamB cannot respond to questions received via email)

Re:Limit on number of open datasets in Delphi


Is there a limit on the number of open and active datasets in Delphi and/or
the component names for these datasets. Ie. are all the datasets stored in a
stack and does that stack have a physical limit.

It's a long shot for my problem already lodged on this news group titled
'Application crashing when attempting to update data row'.

Re:Limit on number of open datasets in Delphi


You might also check into the registry entry MAXFILEHANDLES.  (Use RegEdit to
search)
I routinely raise the default from 48 to 255.  It works for me.
Quote
David Wright wrote:
> Is there a limit on the number of open and active datasets in Delphi and/or
> the component names for these datasets. Ie. are all the datasets stored in a
> stack and does that stack have a physical limit.

> It's a long shot for my problem already lodged on this news group titled
> 'Application crashing when attempting to update data row'.

Re:Limit on number of open datasets in Delphi


Quick question on the max number of files.  If you insert into a paradox
table that has say 10 secondary indices, I'm assuming this is considered 1
table connection (max 127 not BDE 4.01) and 11 open physical files (max 512
not BDE 4.01) from your note.

Also if you have the same physical table open with two different TTable, I
assuming that it is considered 2 connections?

Quote
Bill Todd wrote:
> There are no limits in Delphi. There are limits in the BDE as follows.

> Here are the maximum limits for some common BDE objects.

> General BDE Limitations
> 48 Clients in system
> 32 Sessions per client (3.5 and earlier, 16 Bit, 32 Bit)
> 256 Session per client (4.0, 32 Bit)
> 32 Open databases per session (3.5 and earlier, 16 Bit, 32 Bit)
> 2048 Open databases per session (4.0, 32 Bit)
> 32 Loaded drivers
> 64 Sessions in system (3.5 and earlier, 16 Bit, 32 Bit)
> 12288 Sessions in system (4.0, 32 Bit)
> 4000 Cursors per session
> 16 Entries in error stack
> 8 Table types per driver
> 16 Field types per driver
> 8 Index types per driver
> 48K Size of configuration (IDAPI.CFG) file
> 64K Max size of SQL statement (RequestLive=False)
> 4K Max size of SQL statement (RequestLive=True)
> 6K Max size of SQL statement (RequestLive=True) (NEW BDE 4.01)
> 16K Record buffer size (SQL and ODBC)
> 31 Table and field name size in characters
> 64 Stored procedure name size in characters
> 16 Fields in key
> 3 File extension size in characters
> 260 Table name length in characters (some servers might have other
> limits)
> 260 Path and file name length in characters

> Paradox Limitations
> 127 Tables open per system
> 254 Tables open per system (NEW BDE 4.01)
> 64 Record locks on one table (16Bit) per session
> 255 Record locks on one table (32Bit) per session
> 255 Records in transactions on a table (32 Bit)
> 512 Open physical files (DB, PX, MB, X??, Y??, VAL, TV)
> 1024 Open physical files (DB, PX, MB, X??, Y??, VAL, TV) (NEW BDE 4.01)
> 300 Users in one PDOXUSRS.NET file
> 255 Number of fields per table
> 255 Size of character fields
> 2 Billion records in a table
> 2 Billion bytes in .DB (Table) file
> 10800 Bytes per record for indexed tables
> 32750 Bytes per record for non-indexed tables
> 127 Number of secondary indexes per table
> 16 Number of fields in an index
> 255 Concurrent users per table
> 256 Megabytes of data per BLOb field
> 100 Passwords per session
> 15 Password length
> 63 Passwords per table
> 159 Fields with validity checks (32 Bit)
> 63 Fields with validity checks (16 Bit)

> dBASE Limitations
> 256 Open dBASE tables per system (16 Bit)
> 350 Open dBASE tables per system (BDE 3.0 - 4.0, 32 Bit)
> 512 Open dBASE tables per system (BDE 4.01, 32 Bit) (NEW BDE 4.01)
> 100 Record locks on one dBASE table (16 and 32 Bit)
> 100 Records in transactions on a dBASE table (32 Bit)
> 1 Billion records in a table
> 2 Billion bytes in .DBF (Table) file
> 4000 Size in bytes per record (dBASE 4)
> 32767 Size in bytes per record (dBASE for Windows)
> 255 Number of fields per table (dBASE 4)
> 1024 Number of fields per table (dBASE for Windows)
> 47 Number of index tags per .MDX file
> 254 Size of character fields
> 10 Open master indexes (.MDX) per table
> 220 Key expression length in characters

> Bill

> --

> Bill Todd - TeamB
> (TeamB cannot respond to questions received via email)

Re:Limit on number of open datasets in Delphi


The same table open with two TTables is one connection.

Bill

--

Bill Todd - TeamB
(TeamB cannot respond to questions received via email)

Re:Limit on number of open datasets in Delphi


Quote
Bill Todd wrote:
> There are no limits in Delphi. There are limits in the BDE as follows.

> Here are the maximum limits for some common BDE objects.

> General BDE Limitations
> 48 Clients in system
> 32 Sessions per client (3.5 and earlier, 16 Bit, 32 Bit)
> 256 Session per client (4.0, 32 Bit)
> 32 Open databases per session (3.5 and earlier, 16 Bit, 32 Bit)
> 2048 Open databases per session (4.0, 32 Bit)
> 32 Loaded drivers
> 64 Sessions in system (3.5 and earlier, 16 Bit, 32 Bit)
> 12288 Sessions in system (4.0, 32 Bit)
> 4000 Cursors per session
> 16 Entries in error stack
> 8 Table types per driver
> 16 Field types per driver
> 8 Index types per driver
> 48K Size of configuration (IDAPI.CFG) file
> 64K Max size of SQL statement (RequestLive=False)
> 4K Max size of SQL statement (RequestLive=True)
> 6K Max size of SQL statement (RequestLive=True) (NEW BDE 4.01)
> 16K Record buffer size (SQL and ODBC)
> 31 Table and field name size in characters
> 64 Stored procedure name size in characters
> 16 Fields in key
> 3 File extension size in characters
> 260 Table name length in characters (some servers might have other
> limits)
> 260 Path and file name length in characters

> Paradox Limitations
> 127 Tables open per system
> 254 Tables open per system (NEW BDE 4.01)
> 64 Record locks on one table (16Bit) per session
> 255 Record locks on one table (32Bit) per session
> 255 Records in transactions on a table (32 Bit)
> 512 Open physical files (DB, PX, MB, X??, Y??, VAL, TV)
> 1024 Open physical files (DB, PX, MB, X??, Y??, VAL, TV) (NEW BDE 4.01)
> 300 Users in one PDOXUSRS.NET file
> 255 Number of fields per table
> 255 Size of character fields
> 2 Billion records in a table
> 2 Billion bytes in .DB (Table) file
> 10800 Bytes per record for indexed tables
> 32750 Bytes per record for non-indexed tables
> 127 Number of secondary indexes per table
> 16 Number of fields in an index
> 255 Concurrent users per table
> 256 Megabytes of data per BLOb field
> 100 Passwords per session
> 15 Password length
> 63 Passwords per table
> 159 Fields with validity checks (32 Bit)
> 63 Fields with validity checks (16 Bit)

> dBASE Limitations
> 256 Open dBASE tables per system (16 Bit)
> 350 Open dBASE tables per system (BDE 3.0 - 4.0, 32 Bit)
> 512 Open dBASE tables per system (BDE 4.01, 32 Bit) (NEW BDE 4.01)
> 100 Record locks on one dBASE table (16 and 32 Bit)
> 100 Records in transactions on a dBASE table (32 Bit)
> 1 Billion records in a table
> 2 Billion bytes in .DBF (Table) file
> 4000 Size in bytes per record (dBASE 4)
> 32767 Size in bytes per record (dBASE for Windows)
> 255 Number of fields per table (dBASE 4)
> 1024 Number of fields per table (dBASE for Windows)
> 47 Number of index tags per .MDX file
> 254 Size of character fields
> 10 Open master indexes (.MDX) per table
> 220 Key expression length in characters

> Bill

> --

> Bill Todd - TeamB
> (TeamB cannot respond to questions received via email)

you indicated a DBase limitation of
220 Key expression length in characters.

my experience is that the size of the index key cannot exceed 100
characters.

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