SQLITE: Tweak CREATE TABLE statement and don't catch exceptions.

An 'IF NOT EXISTS' clause was added to the CREATE TABLE query so that
exceptions would not be raised if the table already exists.  Then,
the try/except statements were removed so that other database errors
would be propagated.

Author: Matthew Emmett

pymc/database/sqlite.py

@@ -64,14 +64,10 @@ def _initialize(self, chain, length):
 
         # Create the variable name strings.
         vstr = ', '.join(v + ' FLOAT' for v in var_str(self._shape))
-        
-        try:
-            query = "create table [%s] (recid INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, trace  int(5), %s )" % (self.name, vstr)
-        
-            self.db.cur.execute(query)
-        except OperationalError:
-            "Table already exists"
-            return
+        query = """CREATE TABLE IF NOT EXISTS [%s]
+                     (recid INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
+                      trace  int(5), %s)""" % (self.name, vstr)
+        self.db.cur.execute(query)