SQLite - best practice for opening database - ios

Question

I was in the situation where I've declared sqlite3 variable globally to store database conection and opening database every time without closing it. This lead to memory leaks on my app. I was able to fix this by closing database before open it.
sqlite3 *dbObj;
-(BOOL)openDB
{
//opening database
if (sqlite3_open(dbpath, &dbObj) == SQLITE_OK)
{
NSLog(#"Database opened successfully .....");
return YES;
}
else
{
return NO;
}
}
-(NSArray)getAllTablesInDatabse:(NSString*)database
{
sqlite3_close(dbObj);
[self openDB];
}
This is first way I fixed it.
There's another way I was able to do the same,to check dbObj is nil/NULL in openDB function instead of closing and opening each time. The second way :
-(BOOL)openDB
{
if(dbObj == nil || dbObj == NULL || dbObj = 0)
{
//opening database
if (sqlite3_open(dbpath, &dbObj) == SQLITE_OK)
{
NSLog(#"Database opened successfully .....");
return YES;
}
else
{
return NO;
}
}
else
{
return YES;
}
}
-(NSArray)getAllTablesInDatabse:(NSString*)database
{
[self openDB];
}
Which is best way from performance and other perspective ?

Answer 1

1) It's a good practice to close database after completion of desired task. For example you are creating one table then do like,
NSString *docsDir = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
self.databasePath = [[NSString alloc]initWithString:[docsDir stringByAppendingPathComponent:#"contacts.db"]];
sqlite3_stmt *statement;
if (sqlite3_open([self.databasePath UTF8String], &_contactDB) == SQLITE_OK) {
NSLog(#"database opened successfully");
NSString *query = #"create table if not exists Employee (id integer primary key, name text, surname text, roll text, salary integer)";
const char *queryStatement2 = [query UTF8String];
char *errorMessage;
if (sqlite3_exec(self.contactDB, queryStatement2, NULL, NULL, &errorMessage) == SQLITE_OK) {
if (!errorMessage) {
NSLog(#"table created sucessfully!");
}
else{
NSLog(#"error : %s",errorMessage);
}
}
}
sqlite3_close(self.contactDB);
So, You should close your database every time after use.
2) It is good to check before opening database that if it is open or not compare to close database every time before open.
3) If you close database every time then it will definitely open every time so there is no need to put any condition.