Option to ignore inserts if primary key exists already

Support for SQLite's INSERT OR IGNORE

In the API layer it looks like this:

    fresh_db["test"].insert({"id": 1, "bar": 3}, ignore=True)

For the CLI layer it looks like this:

    $ sqlite-utils insert data.db dogs dogs.json --ignore

Closes #21

sqlite_utils/cli.py

@@ -289,7 +289,7 @@ def insert_upsert_options(fn):
 
 
 def insert_upsert_implementation(
-    path, table, json_file, pk, nl, csv, batch_size, alter, upsert
+    path, table, json_file, pk, nl, csv, batch_size, alter, upsert, ignore=False
 ):
     db = sqlite_utils.Database(path)
     if nl and csv:
@@ -307,14 +307,19 @@ def insert_upsert_implementation(
             docs = [docs]
     if upsert:
         method = db[table].upsert_all
+        extra_kwargs = {}
     else:
         method = db[table].insert_all
-    method(docs, pk=pk, batch_size=batch_size, alter=alter)
+        extra_kwargs = {"ignore": ignore}
+    method(docs, pk=pk, batch_size=batch_size, alter=alter, **extra_kwargs)
 
 
 @cli.command()
 @insert_upsert_options
-def insert(path, table, json_file, pk, nl, csv, batch_size, alter):
+@click.option(
+    "--ignore", is_flag=True, default=False, help="Ignore records if pk already exists"
+)
+def insert(path, table, json_file, pk, nl, csv, batch_size, alter, ignore):
     """
     Insert records from JSON file into a table, creating the table if it
     does not already exist.
@@ -322,7 +327,16 @@ def insert(path, table, json_file, pk, nl, csv, batch_size, alter):
     Input should be a JSON array of objects, unless --nl or --csv is used.
     """
     insert_upsert_implementation(
-        path, table, json_file, pk, nl, csv, batch_size, alter=alter, upsert=False
+        path,
+        table,
+        json_file,
+        pk,
+        nl,
+        csv,
+        batch_size,
+        alter=alter,
+        upsert=False,
+        ignore=ignore,
     )
 
 

sqlite_utils/db.py

@@ -446,6 +446,7 @@ class Table:
         column_order=None,
         hash_id=None,
         alter=False,
+        ignore=False,
     ):
         return self.insert_all(
             [record],
@@ -455,6 +456,7 @@ class Table:
             column_order=column_order,
             hash_id=hash_id,
             alter=alter,
+            ignore=ignore,
         )
 
     def insert_all(
@@ -467,6 +469,7 @@ class Table:
         column_order=None,
         hash_id=None,
         alter=False,
+        ignore=False,
     ):
         """
         Like .insert() but takes a list of records and ensures that the table
@@ -474,6 +477,9 @@ class Table:
         data
         """
         assert not (hash_id and pk), "Use either pk= or hash_id="
+        assert not (
+            ignore and upsert
+        ), "Use either ignore=True or upsert=True, not both"
         all_columns = None
         first = True
         for chunk in chunks(records, batch_size):
@@ -495,10 +501,15 @@ class Table:
                 if hash_id:
                     all_columns.insert(0, hash_id)
             first = False
+            or_what = ""
+            if upsert:
+                or_what = "OR REPLACE "
+            elif ignore:
+                or_what = "OR IGNORE "
             sql = """
-                INSERT {upsert} INTO [{table}] ({columns}) VALUES {rows};
+                INSERT {or_what}INTO [{table}] ({columns}) VALUES {rows};
             """.format(
-                upsert="OR REPLACE" if upsert else "",
+                or_what=or_what,
                 table=self.name,
                 columns=", ".join("[{}]".format(c) for c in all_columns),
                 rows=", ".join(
@@ -530,7 +541,8 @@ class Table:
                         raise
                 self.last_rowid = result.lastrowid
                 self.last_pk = None
-                if hash_id or pk:
+                # self.last_rowid will be 0 if a "INSERT OR IGNORE" happened
+                if (hash_id or pk) and self.last_rowid:
                     self.last_pk = self.db.conn.execute(
                         "select [{}] from [{}] where rowid = ?".format(
                             hash_id or pk, self.name