StarsDB: add possibility for multiple instances of different databases

also fix some typos in the SQL scripts

astrodatagui/db/StarsDB.py

@@ -4,35 +4,37 @@ import sqlite3
 class StarDBError(Enum):
     NO_ERROR = 0
     DB_CONNECTION_FAILED = 1
-    
-DB_NAME = "stars.db"
 
 class StarDB():
-    __instanceVar = None
+    __instances = list()
+    __dbNames = list()
     
     @staticmethod
-    def getInstance():
-        if(StarDB.__instanceVar == None):
-            return StarDB()
+    def getInstance(dbName: str):
+        if(dbName in StarDB.__dbNames):
+            return StarDB.__instances[StarDB.__dbNames.index(dbName)]
         else:
-            return StarDB.__instanceVar
+            instance = StarDB(dbName)
+            StarDB.__instances.append(instance)
+            StarDB.__dbNames.append(dbName)
         
-    def __init__(self):
-        if(StarDB.__instanceVar != None):
-            raise Exception("StarDB cannot be instantiated more than once!")
+    def __init__(self, dbName: str):
+        if(dbName in StarDB.__dbNames):
+            raise Exception(f"StarDB {dbName} cannot be instantiated more than once!")
         else:
-            StarDB.__instanceVar = self
+            StarDB.__dbNames.append(dbName)
+            StarDB.__instances.append(self)
 
         self.error = StarDBError.NO_ERROR
 
         try:
-            con = sqlite3.connect(DB_NAME)
-            self.dbCursor = con.cursor()
+            self.connection = sqlite3.connect(dbName)
+            self.dbCursor = self.connection.cursor()
         except:
             self.error = StarDBError.DB_CONNECTION_FAILED
             
         if(self.error is not StarDBError.NO_ERROR):
-            raise Exception("StarDB cannot connect to the database!")
+            raise Exception(f"StarDB cannot connect to the database: {self.error}")
         else:
             self.initializeDB()
 
@@ -65,10 +67,10 @@ class StarDB():
            sequenceSourceNameID INTEGER NOT NULL,
            sequencesID INTEGER NOT NULL,
            filename TEXT,
-           PRIMARY KEY (starID, seqienceSourceNameID, sequenceStart),
+           PRIMARY KEY (starID, sequenceSourceNameID, sequencesID),
            FOREIGN KEY (starID) REFERENCES starnames(starID),
            FOREIGN KEY (sequenceSourceNameID) REFERENCES sequenceSourceNames(sequenceSourceNameID)
            FOREIGN KEY (sequencesID) REFERENCES sequences(sequencesID)
          );""")
 
-        self.dbCursor.commit()
+        self.connection.commit()