Difference between revisions of "Build SQLite extension on windows"
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v.db.updatethere is following option:
Revision as of 10:36, 12 March 2017
Problem: SQLite lacks by default log(), sqrt(), and other functions.
Solution: Inthere is the following option:
sqliteextra=name Name of SQLite extension file for extra functions (SQLite backend only)
For build SQLite extension for winGRASS follow these steps:
- Install the OSGeo4W directory structure as a build environment by these instructions
- Download extension-functions.c from here and save the file in a folder of your OSGeo4W build environment (e.g. C:\OSGeo4Wdev\src\sqliteextension)
- Download the SQLite source from here, unzip the archive and copy sqlite3.h and sqlite3ext.h in the folder of the step before (e.g. C:\OSGeo4Wdev\src\sqliteextension)
- Open the MSYS Shell offered by your OSGeo4W build environment and change to the SQLite extension directory by e.g. cd "C:\OSGeo4Wdev\src\sqliteextension" (double quotes are needed in the MSYS Shell)
- Then type in the MSYS Shell following command: gcc -fPIC -lm -shared extension-functions.c -o libsqlitefunctions.dll
Then libsqlitefunctions.dll is built and can be used by v.db.update (example from the manual):
g.copy vect=precip_30ynormals,myprecip_30ynormals v.db.addcolumn myprecip_30ynormals column="logjuly double precision" v.db.update myprecip_30ynormals column="logjuly" query_column="log(jul)" \ sqliteextra=C:\OSGeo4Wdev\src\sqliteextension\libsqlitefunctions.dll