How to close database in sqlite in ios? - ios

Question

I am using SqliteDatabase in my project.I am calling a function for data manuplation.
-(void)updateInspectionMapData2:(NSString *)clientid : (NSString *)inspectionid : (NSString *)status
{
NSLog(#"EIGHT");
NSLog(#"inside update data");
const char *dbpath = [databasePath UTF8String];
if (sqlite3_open(dbpath, &database) == SQLITE_OK)
{
NSArray *checkVal = [self getSubClientDataByInspectionId:inspectionid :clientid];
NSLog(#"check is %#",checkVal);
if(checkVal == nil || [checkVal count] == 0)
{
NSString *querySql=[NSString stringWithFormat:
#"UPDATE inspectioninspectormap SET status=\"%#\" where inspectionid = \"%#\" and clientid =\"%#\" and (status = \"1\" or status = \"2\")",status,inspectionid,clientid];
NSLog(#"sql is %#",querySql);
const char *sql=[querySql UTF8String];
if(sqlite3_prepare_v2(database,sql, -1, &statement, NULL) == SQLITE_OK)
{
if(SQLITE_DONE != sqlite3_step(statement))
{
NSLog(#"Error while updating. '%s'", sqlite3_errmsg(database));
}
else
{
sqlite3_reset(statement);
NSLog(#"Update done successfully!");
}
}
sqlite3_finalize(statement);
}
}
sqlite3_close(database);
}
Please tell me is this the right way to close sqlite database.I am not sure i am right because later i get error unable to open database.?

Answer 1

There are many problems with your code. Here's what I see after just a quick glance:
You try to close the database even if it doesn't open.
You try to finalize the prepared statement even if the statement can't be prepared.
You needlessly call sqlite3_reset on the prepared statement.
You build your query using stringWithFormat: instead of properly binding values into the prepared statement.
You are using sqlite3_open instead of sqlite3_open_v2.
You don't log an error if sqlite3_open or sqlite3_prepare_v2 fail.

Answer 2

There is an issue in your code:
This code:
}
sqlite3_finalize(statement);
}
}
sqlite3_close(database);
should be changed to:
}
sqlite3_finalize(statement);
}
sqlite3_close(database);
}
Closing the sqlite should happen right after you finish your work with database, and also within the open connection if loop, but not after the open connection!!!!
When using sqlite, opening and closing should be taken care, else it could lead to lock the database. The problem occurs when you try to open another connection to sqlite without closing the previous one, then your database will be locked .To avoid this, you need make sure that every open connection should have the close connection at the end.
You can try FMDB which is an sqlite wrapper. By using the FMDB,you can simply create the sqlite database using:
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *docsPath = [paths objectAtIndex:0];
NSString *path = [docsPath stringByAppendingPathComponent:#"database.sqlite"];
FMDatabase *database = [FMDatabase databaseWithPath:path];
and you can open the database connection by:
[database open];
and close it by:
[database close];
and to execute a simple statement:
[database executeUpdate:#"create table user(name text primary key, age int)"];
There is a good tutorial out there:

Answer 3

+ (NSString*)setupDatabase
{
NSError *error;
NSString *cachePath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
NSString *dbFilePath = [cachePath stringByAppendingPathComponent:[NSString stringWithFormat:#"%#.%#", DATABASENAME, DATABASETYPE]];
if (! [[NSFileManager defaultManager] fileExistsAtPath:dbFilePath])
{
// if installing the application very first time didn't find db, need to copy
NSString *backupDbPath = [[NSBundle mainBundle] pathForResource:DATABASENAME
ofType:DATABASETYPE];
BOOL copiedBackupDb = [[NSFileManager defaultManager] copyItemAtPath:backupDbPath
toPath:dbFilePath
error:&error];
if (! copiedBackupDb)
{
// copying backup db failed
NSAssert1(0, #"Failed to create writable database file with message '%#'.", [error localizedDescription]);
return nil;
}
}
return dbFilePath;
}
+ (NSString *)getDataBaseFilePath
{
NSString *cachePath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *dbFilePath = [cachePath stringByAppendingPathComponent:[NSString stringWithFormat:#"%#.%#", DATABASENAME, DATABASETYPE]];
return dbFilePath;
}
+(NSString*)selectItem:(NSString*)itemID
{
NSString *name=nil;
NSString* _dataBasePath = [self getDataBaseFilePath];
sqlite3 *database;
if (sqlite3_open([_dataBasePath UTF8String], &database) == SQLITE_OK) {
NSString *query;
query= [NSString stringWithFormat:#"select ITEM_id from Table where IF ITEM_id='%#' ",itemID];
const char *sql=[query UTF8String];
sqlite3_stmt *selectstmt;
if (sqlite3_prepare_v2(database, sql, -1, &selectstmt, NULL)==SQLITE_OK) {
while (sqlite3_step(selectstmt)==SQLITE_ROW) {
if (sqlite3_column_text(selectstmt, 0))
name=[NSString stringWithUTF8String:(char*) sqlite3_column_text(selectstmt, 0)];
}
sqlite3_finalize(selectstmt);
}
}
sqlite3_close(database);
return (name) ;
}
+(BOOL)updateITEM:(ItemObj*)itemObj;
{
NSString* _dataBasePath = [self getDataBaseFilePath];
sqlite3 *database;
if (sqlite3_open([_dataBasePath UTF8String], &database) == SQLITE_OK) {
NSString *qs=[NSString stringWithFormat:#"UPDATE ITEM set User_ID = '%#',User_Name = '%#',Item_id = '%#',User_Status = '%#' WHERE Item_id = '%#'", itemObj.usersid, itemObj.user_name, itemObj.user_id, itemObj.user_status, itemObj.user_id];
const char *sql=[qs UTF8String];
sqlite3_stmt *selectstmt;
if(sqlite3_prepare_v2(database, sql, -1, &selectstmt, NULL) != SQLITE_OK)
return FALSE;
int result = sqlite3_step(selectstmt);
if(result != SQLITE_DONE) return FALSE;
sqlite3_finalize(selectstmt);
}
sqlite3_close(database);
return TRUE;
}