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Overview
Comment: | Documentation on the sqlite_offset() SQL function. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA3-256: |
4ce0a400c292f97c4115de5a521bdf55 |
User & Date: | drh 2018-01-04 19:28:02.519 |
Context
2018-01-08
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12:05 | Add new documentation file zipfile.in. (check-in: 99c2fcc179 user: dan tags: trunk) | |
2018-01-04
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19:28 | Documentation on the sqlite_offset() SQL function. (check-in: 4ce0a400c2 user: drh tags: trunk) | |
19:10 | Flesh out the description of shadow tables and the rtreecheck() function in the R*Tree documentation. (check-in: 2ccafeedbe user: drh tags: trunk) | |
Changes
Changes to pages/changes.in.
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61 62 63 64 65 66 67 | [WITHOUT ROWID] tables. </ol> <li> Added the [https://sqlite.org/src/file/ext/misc/btreeinfo.c|sqlite_btreeinfo] eponymous virtual table for introspecting and estimating the sizes of the btrees in a database. <li> Enhance the [SQLITE_ENABLE_UPDATE_DELETE_LIMIT] compile-time option so that it works for [WITHOUT ROWID] tables. | | | | 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 | [WITHOUT ROWID] tables. </ol> <li> Added the [https://sqlite.org/src/file/ext/misc/btreeinfo.c|sqlite_btreeinfo] eponymous virtual table for introspecting and estimating the sizes of the btrees in a database. <li> Enhance the [SQLITE_ENABLE_UPDATE_DELETE_LIMIT] compile-time option so that it works for [WITHOUT ROWID] tables. <li> Provide the [sqlite_offset(X)] SQL function that returns the byte offset into the database file to the beginning of the record holding value X, when compiling with [-DSQLITE_ENABLE_OFFSET_SQL_FUNC]. } chng {2017-10-24 (3.21.0)} { <li> Take advantage of the atomic-write capabilities in the [https://en.wikipedia.org/wiki/F2FS|F2FS filesystem] when available, for greatly reduced transaction overhead. This currently requires the [SQLITE_ENABLE_BATCH_ATOMIC_WRITE] compile-time option. |
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Changes to pages/compile.in.
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967 968 969 970 971 972 973 974 975 976 977 978 979 980 | databases generated with this option enabled are prone to triggering the [https://www.sqlite.org/src/info/e6e962d6b0f06f46e|e6e962d6b0f06f46] bug in the [sqlite3_blob_reopen()] interface. For those reasons, this optimization is disabled by default. However, this optimization may be enabled by default in a future release of SQLite. } COMPILE_OPTION {SQLITE_ENABLE_PREUPDATE_HOOK} { This option enables [sqlite3_preupdate_hook|several new APIs] that provide callbacks prior to any change to a [rowid table]. The callbacks can be used to record the state of the row before the change occurs. <p>The action of the preupdate hook is similar to the | > > > > > > > > > > > | 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 | databases generated with this option enabled are prone to triggering the [https://www.sqlite.org/src/info/e6e962d6b0f06f46e|e6e962d6b0f06f46] bug in the [sqlite3_blob_reopen()] interface. For those reasons, this optimization is disabled by default. However, this optimization may be enabled by default in a future release of SQLite. } COMPILE_OPTION {SQLITE_ENABLE_OFFSET_SQL_FUNC} { This option enables support for the [sqlite_offset(X)] SQL function. <p> The [sqlite_offset(X)] SQL function requires a new interface on the B-tree storage engine, a new opcode in the [virtual machine] that runs SQL statements, and a new conditional in a critical path of the code generator. To avoid that overhead in applications that do not need the utility of sqlite_offset(X), the function is disabled by default. } COMPILE_OPTION {SQLITE_ENABLE_PREUPDATE_HOOK} { This option enables [sqlite3_preupdate_hook|several new APIs] that provide callbacks prior to any change to a [rowid table]. The callbacks can be used to record the state of the row before the change occurs. <p>The action of the preupdate hook is similar to the |
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Changes to pages/lang.in.
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2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684 | ^The sqlite_compileoption_used() SQL function is a wrapper around the [sqlite3_compileoption_used()] C/C++ function. ^When the argument X to sqlite_compileoption_used(X) is a string which is the name of a compile-time option, this routine returns true (1) or false (0) depending on whether or not that option was used during the build. } funcdef {sqlite_source_id()} {} { ^The sqlite_source_id() function returns a string that identifies the specific version of the source code that was used to build the SQLite library. ^The string returned by sqlite_source_id() is the date and time that the source code was checked in followed by the SHA1 hash for that check-in. ^This function is | > > > > > > > > > > > > > > > | 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 | ^The sqlite_compileoption_used() SQL function is a wrapper around the [sqlite3_compileoption_used()] C/C++ function. ^When the argument X to sqlite_compileoption_used(X) is a string which is the name of a compile-time option, this routine returns true (1) or false (0) depending on whether or not that option was used during the build. } funcdef {sqlite_offset(X)} {} { ^The sqlite_offset(X) function returns the byte offset in the database file for the beginning of the record from which value would be read. If X is not a column in an ordinary table, then sqlite_offset(X) returns NULL. The value returned by sqlite_offset(X) might reference either the original table or an index, depending on the query. If the value X would normally be extracted from an index, the sqlite_offset(X) returns the offset to the corresponding index record. If the value X would be extracted from the original table, then sqlite_offset(X) returns the offset to the table record. <p>The sqlite_offset(X) SQL function is only available if SQLite is built using the [-DSQLITE_ENABLE_OFFSET_SQL_FUNC] compile-time option. } funcdef {sqlite_source_id()} {} { ^The sqlite_source_id() function returns a string that identifies the specific version of the source code that was used to build the SQLite library. ^The string returned by sqlite_source_id() is the date and time that the source code was checked in followed by the SHA1 hash for that check-in. ^This function is |
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