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Which version of SQLite is used:
================================
When embedded SQLITE is used:
* HAVE_SQLITE is *not* defined
* patch it to add the PRAGMA command
* linked as static
When system SQLITE is used:
* HAVE_SQLITE is defined
* obviously not patched for PRAGMA
* linked as dynamic => override the sqlite3CreateFunc function
* For WIN32 (or MacOSX) we would need to use another mechanism (see lattice.umiacs.umd.edu/files/functions_tr.pdf) => impose embedded static lib
Possible solutions in the future:
1 - make SQLite implement the required PRAGMA (patch proposed)
2 - don't use the required PRAGMA at all, and manage to intercept the sqlite3CreateFunc call
when statically linked (=> modify the source code of SQLite)
BLOB handling in SQLite:
========================
SQLite now supports incremental I/O for BLOBS. Any data in any column can be accessed
with this API.
When writing a blob to the database:
------------------------------------
Opening a blob requires the following information:
* the database name
* the table name
* the column name
* the ROWID
The first 3 pieces of information can be obtained from the INSERT or UPDATE statement
itself.
The ROWID can be obtained using sqlite3_last_insert_rowid() for an INSERT or must be queried
for an UPDATE.
When reading a blob from the database:
--------------------------------------
Opening a blob requires the following information:
* the database name: use sqlite3_column_database_name()
* the table name: use sqlite3_column_table_name()
* the column name: use sqlite3_column_origin_name()
* the ROWID: get it from the SELECT as the last row.
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