How to iterate through sqlite_step result - ios

Question

Could someone be so kind as to fill in the few missing pieces of code below. I am struggling with executing an sqlite statement using sqlite3_step, iterating through each row of results and putting the data into a useable format.
Here is the code that creates the database (Database is only two colums)
// Check if database is setup, if not create it
NSString *documents_directory;
NSArray *directory_path;
// Get the documents directory
directory_path = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
documents_directory = [directory_path objectAtIndex:0];
// Build the path to the database file
databasePath = [[NSString alloc] initWithString: [documents_directory stringByAppendingPathComponent: #"weights.db"]];
NSFileManager *file_manager = [NSFileManager defaultManager];
// Create database if it doesn't already exist
if([file_manager fileExistsAtPath: databasePath ] == NO){
const char *database_path = [databasePath UTF8String];
if(sqlite3_open(database_path, &contactDB) == SQLITE_OK){
char *error_message;
const char *sql_statement = "CREATE TABLE IF NOT EXISTS RECORDED_WEIGHTS (ID INTEGER PRIMARY KEY AUTOINCREMENT, WEIGHT TEXT, TIME TEXT)";
if(sqlite3_exec(contactDB, sql_statement, NULL, NULL, &error_message) != SQLITE_OK){
status.text = #"Failed to create table";
}
sqlite3_close(contactDB);
}else{
status.text = #"Failed to open/create database";
}
}
And here is the code I am trying to complete;
// Get info from database and load it.
const char *database_path = [databasePath UTF8String];
sqlite3_stmt *statement;
if(sqlite3_open(database_path, &contactDB) == SQLITE_OK){
NSString *SQLquery = [NSString stringWithFormat:#"SELECT * FROM RECORDED_WEIGHTS ORDER BY TIME DESC"];
const char *query_statement = [SQLquery UTF8String];
if(sqlite3_prepare_v2(contactDB, query_statement, -1, &statement, NULL) == SQLITE_OK){
// Please help me execute statement and get results into useable format here.
}
sqlite3_finalize(statement);
}
sqlite3_close(contactDB);
Thanks in advance.

Answer 1

You want to do something like this:
while(sqlite3_step(statement) == SQLITE_ROW)
{
// int value
int intValue = sqlite3_column_int(statement,fieldIndex);
// string value
NSString* stringValue;
if (sqlite3_column_type(dbps, fieldIndex) != SQLITE_NULL)
{
const char *c = (const char *)sqlite3_column_text(dbps, fieldIndex);
if (c)
{
stringValue = #(c);
}
}
... etc...
}
Look at the documents for the different column types. You can also look at different objective-c wrappers out there to get an idea of how to access the database.