Android SQLite 加入自訂函數

標籤：

SQLite Database 自訂函數實現：

//Here‘s how to create a function that finds the first character of a string.static void firstchar(sqlite3_context *context, int argc, sqlite3_value **argv) {    if (argc == 1) {        char *text = sqlite3_value_text(argv[0]);        if (text && text[0]) {          char result[2];           result[0] = text[0]; result[1] = ‘\0‘;          sqlite3_result_text(context, result, -1, SQLITE_TRANSIENT);          return;        }    }    sqlite3_result_null(context);}//Then attach the function to the database.sqlite3_create_function(db, "firstchar", 1, SQLITE_UTF8, NULL, &firstchar, NULL, NULL);//Finally, use the function in a sql statement.//SELECT firstchar(textfield) from table

 

備忘：aHR0cCUzQS8vd3d3LmNuYmxvZ3MuY29tL3poaGQv

參考代碼：AOSP/external/sqlite/android/sqlite3_android.cpp

參考連結：http://stackoverflow.com/questions/7867099/how-can-i-create-a-user-defined-function-in-sqlite

參考連結：http://www.cnblogs.com/imouto/archive/2013/06/14/how-to-add-user-defined-functions-for-sqlite.html

Android SQLite 加入自訂函數