FMDB - SLC-Cocoaheads

FMDB
SLC Cocoaheads, November 2011
@dnstevenson

- ( NSMutableArray *) getStates{ NSMutableArray *states = [[ NSMutableArray alloc ] init ]; NSString *query = @"SELECT id, name, latitude, longitude FROM states" ; sqlite3_stmt *statement; int result = ( sqlite3_prepare_v2 ( database , [query UTF8String ], - 1 , &statement, nil )); if (result == SQLITE_OK ) { while ( sqlite3_step (statement) == SQLITE_ROW ) { State *state = [[ State alloc ] initWithId : sqlite3_column_int (statement, 0 ) withName :[ self checkForNull :( char *) sqlite3_column_text (statement, 1 )] withLatitude :[ self checkForNull :( char *) sqlite3_column_text (statement, 2 )] withLongitude :[ self checkForNull :( char *) sqlite3_column_text (statement, 3 )]]; [states addObject :state]; [state release ]; } sqlite3_finalize (statement); } return states; }

- ( NSMutableArray *) getStates { NSMutableArray *states = [[ NSMutableArray alloc ] init ]; NSString *query = @"SELECT id, name, latitude, longitude FROM states" ; FMResultSet *rs = [db executeQuery :query]; while ([rs next ]) { State *state = [[ State alloc ] initWithId :[rs intForColumnIndex : 0 ] withName :[rs stringForColumnIndex : 1 ] withLatitude :[rs stringForColumnIndex : 2 ] withLongitude :[rs stringForColumnIndex : 3 ]]; [states addObject :state]; [state release ]; } [rs close ]; return states; }

FMDB
Makes working with SQLite C APIs bearable
It’s not an ORM framework
Works on iOS and Mac

Do This [db executeUpdate : @"insert into test (a, b, c, d, e) values (?, ?, ?, ?, ?)" , @"hi'" , // look! I put in a ', and I'm not escaping it! @"number 10" , [ NSNumber numberWithInt :i], [ NSDate date ], [ NSNumber numberWithFloat : 2.2f ]];

Not This char *errorMsg; char *update = "INSERT INTO favorites (object_id) VALUES (?);" ; sqlite3_stmt *stmt; if ( sqlite3_prepare_v2 ( database , update, - 1 , &stmt, nil ) == SQLITE_OK ) { sqlite3_bind_int (stmt, 1 , objectID); } if ( sqlite3_step (stmt) != SQLITE_DONE ) { NSAssert1 ( 0 , @"Error updating table: %s" , &errorMsg); } sqlite3_finalize (stmt);

Baby Steps
Open Database:
FMDatabase *db = [ FMDatabase databaseWithPath : @"/tmp/tmp.db" ]
Do Something
[db executeUpdate : @"create table test (a text, b text, c integer, d double, e double)" ];
FMResultSet *rs = [db executeQuery : @"select rowid,* from test where a = ?" , @"hi'" ];
NSString *a = [rs stringForColumnIndex : 0 ];

First Step
Need to copy db from bundle to disk
- ( NSString *) dbFilePath {
// Check if the database already exists and if not, copy it over
NSFileManager *fileManager = [ NSFileManager defaultManager ];
NSArray *paths = NSSearchPathForDirectoriesInDomains ( NSDocumentDirectory , NSUserDomainMask , YES );
NSString *documentsDirectory = [paths objectAtIndex : 0 ];
NSString *dbFile = [documentsDirectory stringByAppendingPathComponent : @"user_data.sql3" ];
NSError *error;
if ([fileManager fileExistsAtPath :dbFile] == NO ) {
NSString *pathToDefaultDB = [[ NSBundle mainBundle ] pathForResource : @"user_data" ofType : @"sql3" ];
if ([fileManager copyItemAtPath :pathToDefaultDB toPath :dbFile error :&error] == NO ) {
NSAssert1 ( 0 , @"Failed to copy data with error message '%@'." , [error localizedDescription]);
}
}
return dbFile;
}

Next Steps
Now you have a good path for:
FMDatabase *db = [ FMDatabase databaseWithPath :[ self dbFilePath ]];
Open the db:
[db open ];

Selecting Records FMResultSet *rs = [db executeQuery : @"select * from test where a = ?" , @"hi’" ]; while ([rs next ]) { NSLog ( @"%d %@ %@ %f" , [rs intForColumn : @"c" ], [rs stringForColumn : @"b" ], [rs dateForColumn : @"d" ], [rs doubleForColumn : @"e" ]); } [rs close ]; Note - the parameters passed into executeQuery are quote-safe (escaped)

Inserting Records int i = 0 ; while (i++ < 20 ) { [db executeUpdate : @"insert into test (a, b, c, d, e) values (?, ?, ?, ?, ?)" , @"hi" , [ NSString stringWithFormat : @"number %d" , i], [ NSNumber numberWithInt :i], [ NSDate date ], [ NSNumber numberWithFloat : 2.2f ]]; }

Reading Results
while ([rs next ]) {}
[rs intForColumnIndex : 0 ]
[rs stringForColumnIndex : 1 ]
[rs stringForColumn : @"scientific_name" ];
[rs doubleForColumnIndex : 1 ];
[rs dataForColumnIndex : 1 ];
[rs boolForColumnIndex : 1 ];
[rs longForColumnIndex : 0 ];
[rs objectForColumnIndex : 1 ];
[rs columnIndexIsNull : 1 ];
[rs close ];

Transactions
[db beginTransaction ];
<< some insertions >>
[db commit ];
Checking For Errors if ([db hadError ]) { NSLog ( @"Err %d: %@" , [db lastErrorCode ], [db lastErrorMessage ]); }

More Info
FMDB - https://github.com/ccgus/fmdb
fmdb.m includes lots of examples
Demo Code on GitHub - https://github.com/dnstevenson/US-Landmarks
Ask Me for Help on Twitter: @dnstevenson

FMDB - SLC-Cocoaheads

by Dave Stevenson on Nov 03, 2011

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FMDB - SLC-Cocoaheads — Presentation Transcript