Replaced `SQLDatabaseChain` deprecated direct initialisation with `from_llm` method (#4778)

# Removed usage of deprecated methods

Replaced `SQLDatabaseChain` deprecated direct initialisation with
`from_llm` method

## Who can review?

@hwchase17
@agola11

---------

Co-authored-by: imeckr <chandanroutray2012@gmail.com>
Co-authored-by: Dev 2049 <dev.dev2049@gmail.com>

docs/modules/agents/agents/examples/mrkl.ipynb

@@ -42,7 +42,7 @@
     "search = SerpAPIWrapper()\n",
     "llm_math_chain = LLMMathChain(llm=llm, verbose=True)\n",
     "db = SQLDatabase.from_uri(\"sqlite:///../../../../../notebooks/Chinook.db\")\n",
-    "db_chain = SQLDatabaseChain(llm=llm, database=db, verbose=True)\n",
+    "db_chain = SQLDatabaseChain.from_llm(llm, db, verbose=True)\n",
     "tools = [\n",
     "    Tool(\n",
     "        name = \"Search\",\n",

docs/modules/agents/agents/examples/mrkl_chat.ipynb

@@ -44,7 +44,7 @@
     "search = SerpAPIWrapper()\n",
     "llm_math_chain = LLMMathChain(llm=llm1, verbose=True)\n",
     "db = SQLDatabase.from_uri(\"sqlite:///../../../../../notebooks/Chinook.db\")\n",
-    "db_chain = SQLDatabaseChain(llm=llm1, database=db, verbose=True)\n",
+    "db_chain = SQLDatabaseChain.from_llm(llm1, db, verbose=True)\n",
     "tools = [\n",
     "    Tool(\n",
     "        name = \"Search\",\n",

docs/use_cases/evaluation/sql_qa_benchmarking_chinook.ipynb

@@ -213,7 +213,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "chain = SQLDatabaseChain(llm=llm, database=db, input_key=\"question\")"
+    "chain = SQLDatabaseChain.from_llm(llm, db, input_key=\"question\")"
    ]
   },
   {
@@ -415,7 +415,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.9.1"
+   "version": "3.11.3"
   }
  },
  "nbformat": 4,

langchain/chains/loading.py

@@ -307,7 +307,9 @@ def _load_sql_database_chain(config: dict, **kwargs: Any) -> SQLDatabaseChain:
     if "prompt" in config:
         prompt_config = config.pop("prompt")
         prompt = load_prompt_from_config(prompt_config)
-    return SQLDatabaseChain(database=database, llm=llm, prompt=prompt, **config)
+    else:
+        prompt = None
+    return SQLDatabaseChain.from_llm(llm, database, prompt=prompt, **config)
 
 
 def _load_vector_db_qa_with_sources_chain(

langchain/chains/sql_database/base.py

@@ -223,8 +223,8 @@ class SQLDatabaseSequentialChain(Chain):
         **kwargs: Any,
     ) -> SQLDatabaseSequentialChain:
         """Load the necessary chains."""
-        sql_chain = SQLDatabaseChain(
-            llm=llm, database=database, prompt=query_prompt, **kwargs
+        sql_chain = SQLDatabaseChain.from_llm(
+            llm, database, prompt=query_prompt, **kwargs
         )
         decider_chain = LLMChain(
             llm=llm, prompt=decider_prompt, output_key="table_names"