Swift 5 - Cannot INSERT data into SQLite table after performing SELECT - ios

Question

I am experiencing an issue during iOS app development.
Xcode Version: 11
Swift Version: 5
There are two views for the app - First_View and Second_View.
On the First_View, there is a collection view which is to list out the data in table "custom_location" from SQLite. There is a button on First_View which button is to navigate to Second_View.
On Second_View, there is a collection view which is to list out data in table "all_location" from SQLite. User can select the item and that item will be inserted into table "custom_location".
The behavior of current issue:
If there is any record in table "custom_location", the First_View will display those data when the app is launched. Then I try to click the button to navigate the Second_View and select an item. However, that item cannot be inserted into "custom_location".
I notice if the "custom_location" in the beginning, the Second_View is able to insert data into "custom_location".
Related code for selecting and inserting from SQLite:
public static func getCustomLocationList() -> [Int] {
var customLocationList:[Int] = []
var locationId:Int = -1
var db :SQLiteConnect?
//Database connection path
let urls = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
let sqlitePath = urls[urls.count-1].absoluteString + Settings.dbName
db = SQLiteConnect(path: sqlitePath)
if let mydb = db{
let statement = mydb.fetch("custom_location_list", cond: "location_id > 0", order: "id DESC")
while sqlite3_step(statement) == SQLITE_ROW{
locationId = Int(sqlite3_column_int(statement, 1))
customLocationList.append(locationId)
}
}
return customLocationList
}
public static func insertCustomLocation(_ locationId: Int){
var db :SQLiteConnect?
//Database connection path
let urls = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
let sqlitePath = urls[urls.count-1].absoluteString + Settings.dbName
db = SQLiteConnect(path: sqlitePath)
if let mydb = db {
mydb.insert("custom_location_list", rowInfo: ["location_id":"\(locationId)"])
}
}
In my SQLiteConnect.swift, the function "fetch" and "insert" is:
func fetch(_ tableName :String, cond :String?, order :String?) -> OpaquePointer {
var statement :OpaquePointer? = nil
var sql = "select * from \(tableName)"
if let condition = cond {
sql += " where \(condition)"
}
if let orderBy = order {
sql += " order by \(orderBy)"
}
sqlite3_prepare_v2(self.db, sql.cString(using: String.Encoding.utf8), -1, &statement, nil)
return statement!
}
func insert(_ tableName :String, rowInfo :[String:String]) -> Bool {
var statement :OpaquePointer? = nil
let sql = "insert into \(tableName) " + "(\(rowInfo.keys.joined(separator: ","))) " + "values (\(rowInfo.values.joined(separator: ",")))"
if sqlite3_prepare_v2(self.db, sql.cString(using: String.Encoding.utf8), -1, &statement, nil) == SQLITE_OK {
if sqlite3_step(statement) == SQLITE_DONE {
return true
}
sqlite3_finalize(statement)
}
return false
}

Answer 1

This issue has been fixed.
The root cause is the DB connect is opened on other method and I set "return" in the middle of that function... Then the DB connection has not been terminated when the function is completed.