Minor update to reference other sql tool by tool names instead of hard coded string. (#7514)

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Currently there are 4 tools in SQL agent-toolkits, and 2 of them have
reference to the other 2.

This PR change the reference from hard coded string to `{tool.name}`

Co-authored-by: Junlin Zhou <jlzhou@zjuici.com>

langchain/agents/agent_toolkits/sql/toolkit.py

@@ -33,27 +33,39 @@ class SQLDatabaseToolkit(BaseToolkit):
 
     def get_tools(self) -> List[BaseTool]:
         """Get the tools in the toolkit."""
+        list_sql_database_tool = ListSQLDatabaseTool(db=self.db)
+        info_sql_database_tool_description = (
+            "Input to this tool is a comma-separated list of tables, output is the "
+            "schema and sample rows for those tables. "
+            "Be sure that the tables actually exist by calling "
+            f"{list_sql_database_tool.name} first! "
+            "Example Input: 'table1, table2, table3'"
+        )
+        info_sql_database_tool = InfoSQLDatabaseTool(
+            db=self.db, description=info_sql_database_tool_description
+        )
         query_sql_database_tool_description = (
             "Input to this tool is a detailed and correct SQL query, output is a "
             "result from the database. If the query is not correct, an error message "
             "will be returned. If an error is returned, rewrite the query, check the "
             "query, and try again. If you encounter an issue with Unknown column "
-            "'xxxx' in 'field list', using schema_sql_db to query the correct table "
-            "fields."
+            f"'xxxx' in 'field list', using {info_sql_database_tool.name} "
+            "to query the correct table fields."
         )
-        info_sql_database_tool_description = (
-            "Input to this tool is a comma-separated list of tables, output is the "
-            "schema and sample rows for those tables. "
-            "Be sure that the tables actually exist by calling list_tables_sql_db "
-            "first! Example Input: 'table1, table2, table3'"
+        query_sql_database_tool = QuerySQLDataBaseTool(
+            db=self.db, description=query_sql_database_tool_description
+        )
+        query_sql_checker_tool_description = (
+            "Use this tool to double check if your query is correct before executing "
+            "it. Always use this tool before executing a query with "
+            f"{query_sql_database_tool.name}!"
+        )
+        query_sql_checker_tool = QuerySQLCheckerTool(
+            db=self.db, llm=self.llm, description=query_sql_checker_tool_description
         )
         return [
-            QuerySQLDataBaseTool(
-                db=self.db, description=query_sql_database_tool_description
-            ),
-            InfoSQLDatabaseTool(
-                db=self.db, description=info_sql_database_tool_description
-            ),
-            ListSQLDatabaseTool(db=self.db),
-            QuerySQLCheckerTool(db=self.db, llm=self.llm),
+            query_sql_database_tool,
+            info_sql_database_tool,
+            list_sql_database_tool,
+            query_sql_checker_tool,
         ]