Saving NSArray in SQLite and retrieving it - ios

Question

In my iPHone app I am saving an NSArray in sqlite like this.
-(void)saveData
NSData *dataFromArray = [NSKeyedArchiver archivedDataWithRootObject:MyArray];
sqlite3_stmt *statement;
const char *dbpath = [databasePath UTF8String];
if (sqlite3_open(dbpath, &contactDB) == SQLITE_OK)
{
NSString *insertSQL = [NSString stringWithFormat: #"INSERT INTO ARRAY(PROFILE) VALUES (\"%#\")",dataFromArray];
const char *insert_stmt = [insertSQL UTF8String];
sqlite3_prepare_v2(contactDB, insert_stmt, -1, &statement, NULL);
if (sqlite3_step(statement) == SQLITE_DONE)
{
NSLog(#"Saved Succesfully");
}
else {
// NSAssert1(0, #"Error while inserting data. '%s'", sqlite3_errmsg(contactDB));
NSLog(#"Not saved %d",sqlite3_finalize(statement));
}
sqlite3_finalize(statement);
sqlite3_close(contactDB);
}
}
Data is saved successfully.
Now I tried to fetch the saved data like this-
-(void)fetchData{
const char *dbpath = [databasePath UTF8String];
sqlite3_stmt *statement;
if (sqlite3_open(dbpath, &contactDB) == SQLITE_OK)
{
NSString *querySQL = [NSString stringWithFormat: #"SELECT * FROM ARRAY"];
const char *query_stmt = [querySQL UTF8String];
if (sqlite3_prepare_v2(contactDB, query_stmt, -1, &statement, NULL) == SQLITE_OK)
{
while(sqlite3_step(statement) == SQLITE_ROW)
{
NSString *MYstring = [[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, 0)];
NSData* data = [MYstring dataUsingEncoding:NSUTF8StringEncoding];
NSLog(#"data---%#",data);
NSArray *myArrayFromDB = [NSKeyedUnarchiver unarchiveObjectWithData:data];
}
sqlite3_finalize(statement);
}
sqlite3_close(contactDB);
}
}
I am getting print value for "MYstring" like this
<62706c69 73743030 d4000100 02000300 04000500 0806cb06 cc542474 6f705824 6f626a65 63747358 24766572 73696f6e 59246172 63686976 6572d100 06000754 726f6f74 8001af11 022a0009 000a0017 00180019 001a0080 00810082 00830084 00850086 00870088 0089008a 008b008c 008d008e 008f0090 00910092 00930094 00950096 00970098 0099009a 009b009c 009d009e 009f00a0 00a100a2 00a300a4 00a500a6 00a700a8 00a900aa 00ab00ac 00ad00ae 00af00b0 00b100b5 00bd00c0 00c300c6 00c900cc 00cf00d2 00d500d8 00db00de 00e100e4 00e700ea 00ed00f0 00fd0105 0108010b 010e0111 01140117 011a011d 01200122 0127012a 012d0130 01330136 0139013c 013f0142 01450148 014b014e 01510154 0159015e 01610164 0169016f 018101a1 01a201a3 01a401a5 01a601a7 01a801a9 01aa01ab 01ac01ad 01ae01af 01b201b5 01b801bb 01be01c1 01c401c7 01ca01cd 01d001d3 01d601d9 01f901fa 01fb01fc>
But when I try to create NSArray from data using NSKeyedUnarchiver - the app got crashed showing this error
-[__NSCFData objectForKey:]: unrecognized selector sent to instance
Where I am making the mistake ?
Please help me to retrieve the saved array, Thanks in advance.

Answer 1

Why do you use NSData? Once the string received, write below line
NSArray *myArrayFromDB = [MYstring componentsSeparatedByString:#","];
Try this if it is working. Let me know if not and I find another solution

Answer 2

NSData *dataFromArray = [NSKeyedArchiver archivedDataWithRootObject:myArray];
This creates an XML representation of myArray and places it in dataFromArray. Something like this:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist SYSTEM "file://localhost/System/Library/DTDs/PropertyList.dtd">
<plist version="1.0">
<array>
<string>It is a tale told by an idiot,</string>
<string>Full of sound and fury, signifying nothing.</string>
</array>
</plist>
The XML is converted to UTF8 format and stored in the NSData object.
When you do:
NSString *insertSQL = [NSString stringWithFormat: #"INSERT INTO ARRAY(PROFILE) VALUES (\"%#\")",dataFromArray];
the stringWithFormat operation interprets the format string. When it sees %#, it thinks "I must take the next object reference from the parameter list, apply the description method to it, and place that into the string."
The description method of NSData takes the <?xml version... data and converts it into displayable hex (since description is intended to be used purely for debugging, never "real" code). The displayable hex is formatted in groups of 8 characters, separated by blanks and enclosed in "<>" characters. By now the data is hopelessly garbled, and you haven't even inserted it into the DB yet.