How to enable soundex() in iOS SQLite for a searching query? - ios

Question

Is there a way to use SQLite soundex() in iOS apps?
Please guide me to find a way...
Tried Homegrew but it works on terminal and I need to run soundex everytime in terminal. Also i dont know how to port to iOS APP.
Terminal work

Answer 1

You can the sqlite3_create_function to create the soundex SQL function:
#import "ViewController.h"
#import <sqlite3.h>
void soundex(sqlite3_context *context, int argc, sqlite3_value **argv);
#implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
[self test];
}
- (sqlite3 *)openDatabase
{
NSString *docsPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];
NSString *path = [docsPath stringByAppendingPathComponent:#"test.db"];
NSFileManager *fileManager = [NSFileManager defaultManager];
if (![fileManager fileExistsAtPath:path])
{
NSString *bundlePath = [[NSBundle mainBundle] pathForResource:#"test" ofType:#"db"];
[fileManager copyItemAtPath:bundlePath toPath:path error:nil];
}
sqlite3 *db;
int rc;
if ((rc = sqlite3_open_v2([path UTF8String], &db, SQLITE_OPEN_READWRITE, NULL)) != SQLITE_OK)
{
NSLog(#"%s: sqlite3_open_v2 failed: %d", __FUNCTION__, rc);
}
return db;
}
- (BOOL)createFunction:(sqlite3 *)db
{
int rc;
if ((rc = sqlite3_create_function(db, "soundex", 1, SQLITE_ANY, NULL, soundex, NULL, NULL)) != SQLITE_OK)
{
NSLog(#"%s: sqlite3_create_function error: %s", __FUNCTION__, sqlite3_errmsg(db));
}
return rc;
}
- (void)test
{
int rc;
sqlite3 *db = [self openDatabase];
[self createFunction:db];
sqlite3_stmt *statement;
if (sqlite3_prepare_v2(db, "SELECT name FROM todo WHERE soundex(name) = soundex('Mani')", -1, &statement, NULL) != SQLITE_OK)
{
NSLog(#"%s: sqlite3_prepare_v2 error: %s", __FUNCTION__, sqlite3_errmsg(db));
}
while ((rc = sqlite3_step(statement)) == SQLITE_ROW)
{
const unsigned char *name = sqlite3_column_text(statement, 0);
if (name)
NSLog(#"name=%s", name);
else
NSLog(#"name=NULL");
}
if (rc != SQLITE_DONE)
{
NSLog(#"%s: sqlite3_step error: %s", __FUNCTION__, sqlite3_errmsg(db));
}
sqlite3_finalize(statement);
sqlite3_close(db);
}
#end
void soundex(sqlite3_context *context, int argc, sqlite3_value **argv)
{
const char *str = (const char*)sqlite3_value_text(argv[0]);
const char *in = str;
static int code[] =
{ 0,1,2,3,0,1,2,0,0,2,2,4,5,5,0,1,2,6,2,3,0,1,0,2,0,2 };
/* a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z */
char ch;
int last;
int count;
char key[5];
/* Set up default key, complete with trailing '0's */
strcpy(key, "Z000");
/* Advance to the first letter. If none present,
return default key */
while (*in != '\0' && !isalpha(*in))
++in;
if (*in == '\0') {
sqlite3_result_text(context, key, 4, SQLITE_TRANSIENT);
return;
}
/* Pull out the first letter, uppercase it, and
set up for main loop */
key[0] = toupper(*in);
last = code[key[0] - 'A'];
++in;
/* Scan rest of string, stop at end of string or
when the key is full */
for (count = 1; count < 4 && *in != '\0'; ++in) {
/* If non-alpha, ignore the character altogether */
if (isalpha(*in)) {
ch = tolower(*in);
/* Fold together adjacent letters sharing the same code */
if (last != code[ch - 'a']) {
last = code[ch - 'a'];
/* Ignore code==0 letters except as separators */
if (last != 0)
key[count++] = '0' + last;
}
}
}
sqlite3_result_text(context, key, 4, SQLITE_TRANSIENT);
}

Answer 2

You need to include the sqlite.c/sqlite.h files in your project from the sqlite amalgamation itself vs. using the libsqlite dylib.
Be sure to set the SQLITE_SOUNDEX preprocessor flag as well to include this feature when you build.
1) download and unzip the sqlite amalgamation. Add the sqlite.h/sqlite.c files to your project.
2) add SQLITE_SOUNDEX=1 to your project's Preprocessor Macros, via the Build Settings screen in XCode.
3) remove libsqlite3XXX.dylib from your project's Link With Libraries list, via the Build Phases screen in Xcode.