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SQLite training in Houston TX on 2019-11-05 (details)
Part of the 2019 Tcl Conference

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Overview
Comment:Updates to the sqlite3_vtab_nochange() documentation. No changes to code.
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SHA3-256: 5bd99abc10b8153aadff5f815ae15fbe375f34f043c65def4be03014d2efdb50
User & Date: drh 2018-05-24 13:59:45
Context
2018-05-24
16:18
Addition cases for rtree preformance testing in speedtest1.c. Add the --nodiff option to the speed-check.sh script. check-in: 95f2d62c user: drh tags: trunk
13:59
Updates to the sqlite3_vtab_nochange() documentation. No changes to code. check-in: 5bd99abc user: drh tags: trunk
2018-05-23
17:53
Remove a branch that is no longer used due to the fix to the sqlite_sequence schema problem, ticket [d8dc2b3a58cd5dc2918a1d4acbba4676a23ada4c] check-in: 06674269 user: drh tags: trunk
Changes
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Changes to src/sqlite.h.in.

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/*
** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE
**
** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn]
** method of a [virtual table], then it returns true if and only if the
** column is being fetched as part of an UPDATE operation during which the
** column value will not change.  Applications might use this to substitute
** a lighter-weight value to return that the corresponding [xUpdate] method
** understands as a "no-change" value.
**
** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that
** the column is not changed by the UPDATE statement, they the xColumn
** method can optionally return without setting a result, without calling
** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces].
** In that case, [sqlite3_value_nochange(X)] will return true for the
** same column in the [xUpdate] method.
*/
int sqlite3_vtab_nochange(sqlite3_context*);








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/*
** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE
**
** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn]
** method of a [virtual table], then it returns true if and only if the
** column is being fetched as part of an UPDATE operation during which the
** column value will not change.  Applications might use this to substitute
** a return value that is less expensive to compute and that the corresponding
** [xUpdate] method understands as a "no-change" value.
**
** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that
** the column is not changed by the UPDATE statement, then the xColumn
** method can optionally return without setting a result, without calling
** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces].
** In that case, [sqlite3_value_nochange(X)] will return true for the
** same column in the [xUpdate] method.
*/
int sqlite3_vtab_nochange(sqlite3_context*);