[sqlite] Using incremental BLOB functions against a BLOB column in a virtual table
On Wed, Feb 25, 2015 at 7:52 AM, Hick Gunter wrote: > And the "explain" output will contain virtual table opcodes > I use this technique to discover which tables and virtual tables a view accesses (instead of trying to parse the query.) I execute "explain select rowid from $viewname", and look for TableLock and VOpen "opcode"s, and look at the "p4" column for table names and for virtual tables, p4 contains vtab:module-hex-address:vtable-hex-address, where module-hex-address is your sqlite3_module* in hexadecimal, and vtable-address your sqlite3_vtab*, which typically you code can translate to the vtable names. --DD
[sqlite] Using incremental BLOB functions against a BLOB column in a virtual table
Yes. The stored SQL string will contain the keyword "VIRTUAL". asql> select sql from sqlite_master where name='sgb_dd_draw'; sql - CREATE VIRTUAL TABLE sgb_dd_draw USING Partition ( 'sgbDrawDefPartitionDM-PARTITION_ACISQL.xml', sgb_dd_draw ) And the "explain" output will contain virtual table opcodes asql> explain select jurisdiction_no, game_no from sgb_dd_draw limit 1; addr opcode p1p2p3p4 p5 comment - - -- - ? 3 VOpen 0 0 0 vtab:1D46D128:2B9BCF7769D0 00 NULL .. 6 VFilter0 122 00 NULL 7 VColumn0 0 400 sgb_dd_draw.jurisdiction_no 8 VColumn0 1 500 sgb_dd_draw.game_no ? -Urspr?ngliche Nachricht- Von: Evans, Randall [mailto:REvans at seasoft.com] Gesendet: Dienstag, 24. Februar 2015 20:18 An: sqlite-users at mailinglists.sqlite.org Betreff: Re: [sqlite] Using incremental BLOB functions against a BLOB column in a virtual table Thanks to Richard Hipp and Hick Gunter for their replies on this topic. Given that support for support for BLOBs in virtual tables differs from that for BLOBs in physical tables, is there any method or function available to the sqlite3_x() caller that can be used to distinguish tables defined as virtual tables vs. physical tables? Thanks in advance for any assistance provided. Randy Evans > > From: Richard Hipp mailto:drh at sqlite.org>> > > On 2/23/15, Evans, Randall mailto:REvans at > seasoft.com>> wrote: > > Can the incremental BLOB functions (sqlite_blob_open(), > > sqlite_blob_read(), > > etc) access BLOB column data defined in a SQLite virtual table? If > > it matters, I am only interested in read-only access at this time. > > no. > > > > > If the answer is yes, is there any facility in virtual table support > > for xColumn or any other method that will expose to the virtual > > table module the positioning/length values supplied as the 3rd and > > 4th arguments of the > > sqlite_blob_read() function (N bytes and offset values)? > > There would have to be, in order for incremental blob I/O to be > supported on virtual tables. The absence of such a method is one > reason why the answer above is "no". > > > > > > > Randy Evans ___ sqlite-users mailing list sqlite-users at mailinglists.sqlite.org<mailto:sqlite-users at mailinglists.sqlite.org> http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users ___ Gunter Hick Software Engineer Scientific Games International GmbH FN 157284 a, HG Wien Klitschgasse 2-4, A-1130 Vienna,Austria Tel: +43 1 80100 - 0 E-Mail: hick at scigames.at This communication (including any attachments) is intended for the use of the intended recipient(s) only and may contain information that is confidential, privileged or legally protected. Any unauthorized use or dissemination of this communication is strictly prohibited. If you have received this communication in error, please immediately notify the sender by return e-mail message and delete all copies of the original communication. Thank you for your cooperation.
[sqlite] Using incremental BLOB functions against a BLOB column in a virtual table
Thanks to Richard Hipp and Hick Gunter for their replies on this topic. Given that support for support for BLOBs in virtual tables differs from that for BLOBs in physical tables, is there any method or function available to the sqlite3_x() caller that can be used to distinguish tables defined as virtual tables vs. physical tables? Thanks in advance for any assistance provided. Randy Evans > > From: Richard Hipp > > On 2/23/15, Evans, Randall wrote: > > Can the incremental BLOB functions (sqlite_blob_open(), > > sqlite_blob_read(), > > etc) access BLOB column data defined in a SQLite virtual table? If it > > matters, I am only interested in read-only access at this time. > > no. > > > > > If the answer is yes, is there any facility in virtual table support > > for xColumn or any other method that will expose to the virtual table > > module the positioning/length values supplied as the 3rd and 4th > > arguments of the > > sqlite_blob_read() function (N bytes and offset values)? > > There would have to be, in order for incremental blob I/O to be supported > on virtual tables. The absence of such a method is one reason why the > answer above is "no". > > > > > > > Randy Evans
[sqlite] Using incremental BLOB functions against a BLOB column in a virtual table
Incremental BLOB I/O makes certain assertions that cannot be guaranteed (much less verified at runtime) for virtual tables (e.g. 1: unique rowids that 2: can be used for access) and needs to know how to read/write them (which is under the control of the virtual table author). -Urspr?ngliche Nachricht- Von: Evans, Randall [mailto:REvans at seasoft.com] Gesendet: Dienstag, 24. Februar 2015 01:47 An: sqlite-users at mailinglists.sqlite.org Betreff: [sqlite] Using incremental BLOB functions against a BLOB column in a virtual table Can the incremental BLOB functions (sqlite_blob_open(), sqlite_blob_read(), etc) access BLOB column data defined in a SQLite virtual table? If it matters, I am only interested in read-only access at this time. If the answer is yes, is there any facility in virtual table support for xColumn or any other method that will expose to the virtual table module the positioning/length values supplied as the 3rd and 4th arguments of the sqlite_blob_read() function (N bytes and offset values)? Randy Evans ___ sqlite-users mailing list sqlite-users at mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users ___ Gunter Hick Software Engineer Scientific Games International GmbH FN 157284 a, HG Wien Klitschgasse 2-4, A-1130 Vienna, Austria Tel: +43 1 80100 0 E-Mail: hick at scigames.at This communication (including any attachments) is intended for the use of the intended recipient(s) only and may contain information that is confidential, privileged or legally protected. Any unauthorized use or dissemination of this communication is strictly prohibited. If you have received this communication in error, please immediately notify the sender by return e-mail message and delete all copies of the original communication. Thank you for your cooperation.
[sqlite] Using incremental BLOB functions against a BLOB column in a virtual table
On 2/23/15, Evans, Randall wrote: > Can the incremental BLOB functions (sqlite_blob_open(), sqlite_blob_read(), > etc) access BLOB column data defined in a SQLite virtual table? If it > matters, I am only interested in read-only access at this time. no. > > If the answer is yes, is there any facility in virtual table support for > xColumn or any other method that will expose to the virtual table module the > positioning/length values supplied as the 3rd and 4th arguments of the > sqlite_blob_read() function (N bytes and offset values)? There would have to be, in order for incremental blob I/O to be supported on virtual tables. The absence of such a method is one reason why the answer above is "no". > > > Randy Evans > ___ > sqlite-users mailing list > sqlite-users at mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > -- D. Richard Hipp drh at sqlite.org
[sqlite] Using incremental BLOB functions against a BLOB column in a virtual table
Can the incremental BLOB functions (sqlite_blob_open(), sqlite_blob_read(), etc) access BLOB column data defined in a SQLite virtual table? If it matters, I am only interested in read-only access at this time. If the answer is yes, is there any facility in virtual table support for xColumn or any other method that will expose to the virtual table module the positioning/length values supplied as the 3rd and 4th arguments of the sqlite_blob_read() function (N bytes and offset values)? Randy Evans
