高级文本转SQL工作流
在本指南中,我们将向您展示如何使用我们的工作流语法为您的数据设置文本到SQL的工作流程。
这为您提供了灵活性,可以通过额外技术增强文本到SQL功能。我们在以下章节中展示这些内容:
- 查询时表检索: 在文本转SQL提示中动态检索相关表。
- 查询时样本行检索: 对每行进行嵌入/索引,并在文本到SQL提示中为每个表动态检索示例行。
我们的开箱即用工作流包括 NLSQLTableQueryEngine 和 SQLTableRetrieverQueryEngine。(若想查看使用这些模块的文本转SQL指南,请点击此处)。本指南实现了这些模块的高级版本,为您提供最大灵活性以应用于自身场景。
NOTE: Any Text-to-SQL application should be aware that executing arbitrary SQL queries can be a security risk. It is recommended to take precautions as needed, such as using restricted roles, read-only databases, sandboxing, etc.
我们使用WikiTableQuestions数据集(Pasupat和Liang 2015)作为我们的测试数据集。
我们遍历文件夹中的所有CSV文件,将每个文件存储到SQLite数据库中(随后我们将在每个表结构上构建对象索引)。
%pip install llama-index-llms-openai!wget "https://github.com/ppasupat/WikiTableQuestions/releases/download/v1.0.2/WikiTableQuestions-1.0.2-compact.zip" -O data.zip!unzip data.zipimport pandas as pdfrom pathlib import Path
data_dir = Path("./WikiTableQuestions/csv/200-csv")csv_files = sorted([f for f in data_dir.glob("*.csv")])dfs = []for csv_file in csv_files: print(f"processing file: {csv_file}") try: df = pd.read_csv(csv_file) dfs.append(df) except Exception as e: print(f"Error parsing {csv_file}: {str(e)}")这里我们使用 gpt-4o-mini 通过我们的 Pydantic 程序从每个表中提取表名(带下划线)和摘要。
tableinfo_dir = "WikiTableQuestions_TableInfo"!mkdir {tableinfo_dir}mkdir: WikiTableQuestions_TableInfo: File existsfrom llama_index.core.prompts import ChatPromptTemplatefrom llama_index.core.bridge.pydantic import BaseModel, Fieldfrom llama_index.llms.openai import OpenAIfrom llama_index.core.llms import ChatMessage
class TableInfo(BaseModel): """Information regarding a structured table."""
table_name: str = Field( ..., description="table name (must be underscores and NO spaces)" ) table_summary: str = Field( ..., description="short, concise summary/caption of the table" )
prompt_str = """\Give me a summary of the table with the following JSON format.
- The table name must be unique to the table and describe it while being concise.- Do NOT output a generic table name (e.g. table, my_table).
Do NOT make the table name one of the following: {exclude_table_name_list}
Table:{table_str}
Summary: """prompt_tmpl = ChatPromptTemplate( message_templates=[ChatMessage.from_str(prompt_str, role="user")])
llm = OpenAI(model="gpt-4o-mini")import json
def _get_tableinfo_with_index(idx: int) -> str: results_gen = Path(tableinfo_dir).glob(f"{idx}_*") results_list = list(results_gen) if len(results_list) == 0: return None elif len(results_list) == 1: path = results_list[0] return TableInfo.parse_file(path) else: raise ValueError( f"More than one file matching index: {list(results_gen)}" )
table_names = set()table_infos = []for idx, df in enumerate(dfs): table_info = _get_tableinfo_with_index(idx) if table_info: table_infos.append(table_info) else: while True: df_str = df.head(10).to_csv() table_info = llm.structured_predict( TableInfo, prompt_tmpl, table_str=df_str, exclude_table_name_list=str(list(table_names)), ) table_name = table_info.table_name print(f"Processed table: {table_name}") if table_name not in table_names: table_names.add(table_name) break else: # try again print(f"Table name {table_name} already exists, trying again.") pass
out_file = f"{tableinfo_dir}/{idx}_{table_name}.json" json.dump(table_info.dict(), open(out_file, "w")) table_infos.append(table_info)将数据存入SQL数据库
Section titled “Put Data in SQL Database”我们使用 sqlalchemy,一个流行的SQL数据库工具包,来加载所有表格。
# put data into sqlite dbfrom sqlalchemy import ( create_engine, MetaData, Table, Column, String, Integer,)import re
# Function to create a sanitized column namedef sanitize_column_name(col_name): # Remove special characters and replace spaces with underscores return re.sub(r"\W+", "_", col_name)
# Function to create a table from a DataFrame using SQLAlchemydef create_table_from_dataframe( df: pd.DataFrame, table_name: str, engine, metadata_obj): # Sanitize column names sanitized_columns = {col: sanitize_column_name(col) for col in df.columns} df = df.rename(columns=sanitized_columns)
# Dynamically create columns based on DataFrame columns and data types columns = [ Column(col, String if dtype == "object" else Integer) for col, dtype in zip(df.columns, df.dtypes) ]
# Create a table with the defined columns table = Table(table_name, metadata_obj, *columns)
# Create the table in the database metadata_obj.create_all(engine)
# Insert data from DataFrame into the table with engine.connect() as conn: for _, row in df.iterrows(): insert_stmt = table.insert().values(**row.to_dict()) conn.execute(insert_stmt) conn.commit()
# engine = create_engine("sqlite:///:memory:")engine = create_engine("sqlite:///wiki_table_questions.db")metadata_obj = MetaData()for idx, df in enumerate(dfs): tableinfo = _get_tableinfo_with_index(idx) print(f"Creating table: {tableinfo.table_name}") create_table_from_dataframe(df, tableinfo.table_name, engine, metadata_obj)# # setup Arize Phoenix for logging/observability# import phoenix as px# import llama_index.core
# px.launch_app()# llama_index.core.set_global_handler("arize_phoenix")高级功能1:支持查询时表检索的文本转SQL。
Section titled “Advanced Capability 1: Text-to-SQL with Query-Time Table Retrieval.”现在我们将向您展示如何设置一个端到端的文本转SQL与表格检索系统。
这里我们定义核心模块。
- 对象索引 + 检索器用于存储表结构
- 用于连接上述表格和SQLRetriever的SQLDatabase对象。
- 文本转SQL提示
- 响应合成提示
- 大语言模型
对象索引、检索器、SQL数据库
from llama_index.core.objects import ( SQLTableNodeMapping, ObjectIndex, SQLTableSchema,)from llama_index.core import SQLDatabase, VectorStoreIndex
sql_database = SQLDatabase(engine)
table_node_mapping = SQLTableNodeMapping(sql_database)table_schema_objs = [ SQLTableSchema(table_name=t.table_name, context_str=t.table_summary) for t in table_infos] # add a SQLTableSchema for each table
obj_index = ObjectIndex.from_objects( table_schema_objs, table_node_mapping, VectorStoreIndex,)obj_retriever = obj_index.as_retriever(similarity_top_k=3)SQL检索器 + 表格解析器
from llama_index.core.retrievers import SQLRetrieverfrom typing import List
sql_retriever = SQLRetriever(sql_database)
def get_table_context_str(table_schema_objs: List[SQLTableSchema]): """Get table context string.""" context_strs = [] for table_schema_obj in table_schema_objs: table_info = sql_database.get_single_table_info( table_schema_obj.table_name ) if table_schema_obj.context_str: table_opt_context = " The table description is: " table_opt_context += table_schema_obj.context_str table_info += table_opt_context
context_strs.append(table_info) return "\n\n".join(context_strs)文本到SQL提示 + 输出解析器
from llama_index.core.prompts.default_prompts import DEFAULT_TEXT_TO_SQL_PROMPTfrom llama_index.core import PromptTemplatefrom llama_index.core.llms import ChatResponse
def parse_response_to_sql(chat_response: ChatResponse) -> str: """Parse response to SQL.""" response = chat_response.message.content sql_query_start = response.find("SQLQuery:") if sql_query_start != -1: response = response[sql_query_start:] # TODO: move to removeprefix after Python 3.9+ if response.startswith("SQLQuery:"): response = response[len("SQLQuery:") :] sql_result_start = response.find("SQLResult:") if sql_result_start != -1: response = response[:sql_result_start] return response.strip().strip("```").strip()
text2sql_prompt = DEFAULT_TEXT_TO_SQL_PROMPT.partial_format( dialect=engine.dialect.name)print(text2sql_prompt.template)Given an input question, first create a syntactically correct {dialect} query to run, then look at the results of the query and return the answer. You can order the results by a relevant column to return the most interesting examples in the database.
Never query for all the columns from a specific table, only ask for a few relevant columns given the question.
Pay attention to use only the column names that you can see in the schema description. Be careful to not query for columns that do not exist. Pay attention to which column is in which table. Also, qualify column names with the table name when needed. You are required to use the following format, each taking one line:
Question: Question hereSQLQuery: SQL Query to runSQLResult: Result of the SQLQueryAnswer: Final answer here
Only use tables listed below.{schema}
Question: {query_str}SQLQuery:响应合成提示
response_synthesis_prompt_str = ( "Given an input question, synthesize a response from the query results.\n" "Query: {query_str}\n" "SQL: {sql_query}\n" "SQL Response: {context_str}\n" "Response: ")response_synthesis_prompt = PromptTemplate( response_synthesis_prompt_str,)# llm = OpenAI(model="gpt-3.5-turbo")llm = OpenAI(model="gpt-4o-mini")现在组件已经就位,让我们定义完整的工作流程!
from llama_index.core.workflow import ( Workflow, StartEvent, StopEvent, step, Context, Event,)
class TableRetrieveEvent(Event): """Result of running table retrieval."""
table_context_str: str query: str
class TextToSQLEvent(Event): """Text-to-SQL event."""
sql: str query: str
class TextToSQLWorkflow1(Workflow): """Text-to-SQL Workflow that does query-time table retrieval."""
def __init__( self, obj_retriever, text2sql_prompt, sql_retriever, response_synthesis_prompt, llm, *args, **kwargs, ) -> None: """Init params.""" super().__init__(*args, **kwargs) self.obj_retriever = obj_retriever self.text2sql_prompt = text2sql_prompt self.sql_retriever = sql_retriever self.response_synthesis_prompt = response_synthesis_prompt self.llm = llm
@step def retrieve_tables( self, ctx: Context, ev: StartEvent ) -> TableRetrieveEvent: """Retrieve tables.""" table_schema_objs = self.obj_retriever.retrieve(ev.query) table_context_str = get_table_context_str(table_schema_objs) return TableRetrieveEvent( table_context_str=table_context_str, query=ev.query )
@step def generate_sql( self, ctx: Context, ev: TableRetrieveEvent ) -> TextToSQLEvent: """Generate SQL statement.""" fmt_messages = self.text2sql_prompt.format_messages( query_str=ev.query, schema=ev.table_context_str ) chat_response = self.llm.chat(fmt_messages) sql = parse_response_to_sql(chat_response) return TextToSQLEvent(sql=sql, query=ev.query)
@step def generate_response(self, ctx: Context, ev: TextToSQLEvent) -> StopEvent: """Run SQL retrieval and generate response.""" retrieved_rows = self.sql_retriever.retrieve(ev.sql) fmt_messages = self.response_synthesis_prompt.format_messages( sql_query=ev.sql, context_str=str(retrieved_rows), query_str=ev.query, ) chat_response = llm.chat(fmt_messages) return StopEvent(result=chat_response)工作流的一个非常棒的特性是,你既可以可视化执行图,也可以查看最近一次执行的追踪记录。
from llama_index.utils.workflow import draw_all_possible_flows
draw_all_possible_flows( TextToSQLWorkflow1, filename="text_to_sql_table_retrieval.html")text_to_sql_table_retrieval.htmlfrom IPython.display import display, HTML
# Read the contents of the HTML filewith open("text_to_sql_table_retrieval.html", "r") as file: html_content = file.read()
# Display the HTML contentdisplay(HTML(html_content))现在我们准备在整个工作流中运行一些查询。
workflow = TextToSQLWorkflow1( obj_retriever, text2sql_prompt, sql_retriever, response_synthesis_prompt, llm, verbose=True,)response = await workflow.run( query="What was the year that The Notorious B.I.G was signed to Bad Boy?")print(str(response))Running step retrieve_tablesStep retrieve_tables produced event TableRetrieveEventRunning step generate_sqlStep generate_sql produced event TextToSQLEventRunning step generate_responseStep generate_response produced event StopEventassistant: The Notorious B.I.G was signed to Bad Boy Records in 1993.VERBOSE: True> Table Info: Table 'bad_boy_artists_album_release_summary' has columns: Act (VARCHAR), Year_signed (INTEGER), _Albums_released_under_Bad_Boy (VARCHAR), . The table description is: A summary of artists signed to Bad Boy Records along with the year they were signed and the number of albums they released.Here are some relevant example rows (values in the same order as columns above)('The Notorious B.I.G', 1993, '5')
> Table Info: Table 'filmography_of_diane_drummond' has columns: Year (INTEGER), Title (VARCHAR), Role (VARCHAR), Notes (VARCHAR), . The table description is: A list of film and television roles played by Diane Drummond from 1995 to 2001.Here are some relevant example rows (values in the same order as columns above)(2013, 'L.A. Slasher', 'The Actress', None)
> Table Info: Table 'progressive_rock_album_chart_positions' has columns: Year (INTEGER), Title (VARCHAR), Chart_Positions_UK (VARCHAR), Chart_Positions_US (VARCHAR), Chart_Positions_NL (VARCHAR), Comments (VARCHAR), . The table description is: Chart positions of progressive rock albums in the UK, US, and NL from 1969 to 1981.Here are some relevant example rows (values in the same order as columns above)(1977, 'Novella', '–', '46', '–', '1977 (January in US, August in UK, as the band moved to the Warner Bros Music Group)')
VERBOSE: True> Table Info: Table 'bad_boy_artists_album_release_summary' has columns: Act (VARCHAR), Year_signed (INTEGER), _Albums_released_under_Bad_Boy (VARCHAR), . The table description is: A summary of artists signed to Bad Boy Records along with the year they were signed and the number of albums they released.Here are some relevant example rows (values in the same order as columns above)('The Notorious B.I.G', 1993, '5')
> Table Info: Table 'filmography_of_diane_drummond' has columns: Year (INTEGER), Title (VARCHAR), Role (VARCHAR), Notes (VARCHAR), . The table description is: A list of film and television roles played by Diane Drummond from 1995 to 2001.Here are some relevant example rows (values in the same order as columns above)(2013, 'L.A. Slasher', 'The Actress', None)
> Table Info: Table 'progressive_rock_album_chart_positions' has columns: Year (INTEGER), Title (VARCHAR), Chart_Positions_UK (VARCHAR), Chart_Positions_US (VARCHAR), Chart_Positions_NL (VARCHAR), Comments (VARCHAR), . The table description is: Chart positions of progressive rock albums in the UK, US, and NL from 1969 to 1981.Here are some relevant example rows (values in the same order as columns above)(1977, 'Novella', '–', '46', '–', '1977 (January in US, August in UK, as the band moved to the Warner Bros Music Group)')response = await workflow.run( query="Who won best director in the 1972 academy awards")print(str(response))Running step retrieve_tablesStep retrieve_tables produced event TableRetrieveEventRunning step generate_sqlStep generate_sql produced event TextToSQLEventRunning step generate_responseStep generate_response produced event StopEventassistant: William Friedkin won the Best Director award at the 1972 Academy Awards.response = await workflow.run(query="What was the term of Pasquale Preziosa?")print(str(response))Running step retrieve_tablesStep retrieve_tables produced event TableRetrieveEventRunning step generate_sqlStep generate_sql produced event TextToSQLEventRunning step generate_responseStep generate_response produced event StopEventassistant: Pasquale Preziosa has been serving since 25 February 2013 and is currently in office as the incumbent.2. 高级能力 2:支持查询时行检索(及表检索)的文本转SQL
Section titled “2. Advanced Capability 2: Text-to-SQL with Query-Time Row Retrieval (along with Table Retrieval)”上一个示例中的一个问题是,如果用户查询“The Notorious BIG”,但艺术家在数据库中存储为“The Notorious B.I.G”,那么生成的SELECT语句很可能不会返回任何匹配结果。
我们可以通过获取每个表的少量示例行来缓解这个问题。一种简单的方法是直接取前k行。相反,我们根据用户查询对k个相关行进行嵌入、索引和检索,为文本转SQL的LLM提供最具上下文相关性的信息以生成SQL。
我们现在扩展我们的工作流程。
我们对每个表格的行进行嵌入/索引,从而为每个表格生成一个索引。
from llama_index.core import VectorStoreIndex, load_index_from_storagefrom sqlalchemy import textfrom llama_index.core.schema import TextNodefrom llama_index.core import StorageContextimport osfrom pathlib import Pathfrom typing import Dict
def index_all_tables( sql_database: SQLDatabase, table_index_dir: str = "table_index_dir") -> Dict[str, VectorStoreIndex]: """Index all tables.""" if not Path(table_index_dir).exists(): os.makedirs(table_index_dir)
vector_index_dict = {} engine = sql_database.engine for table_name in sql_database.get_usable_table_names(): print(f"Indexing rows in table: {table_name}") if not os.path.exists(f"{table_index_dir}/{table_name}"): # get all rows from table with engine.connect() as conn: cursor = conn.execute(text(f'SELECT * FROM "{table_name}"')) result = cursor.fetchall() row_tups = [] for row in result: row_tups.append(tuple(row))
# index each row, put into vector store index nodes = [TextNode(text=str(t)) for t in row_tups]
# put into vector store index (use OpenAIEmbeddings by default) index = VectorStoreIndex(nodes)
# save index index.set_index_id("vector_index") index.storage_context.persist(f"{table_index_dir}/{table_name}") else: # rebuild storage context storage_context = StorageContext.from_defaults( persist_dir=f"{table_index_dir}/{table_name}" ) # load index index = load_index_from_storage( storage_context, index_id="vector_index" ) vector_index_dict[table_name] = index
return vector_index_dict
vector_index_dict = index_all_tables(sql_database)Indexing rows in table: academy_awards_and_nominations_1972Indexing rows in table: annual_traffic_accident_deathsIndexing rows in table: bad_boy_artists_album_release_summaryIndexing rows in table: bbc_radio_services_cost_comparison_2012_2013Indexing rows in table: binary_encoding_probabilitiesIndexing rows in table: boxing_match_results_summaryIndexing rows in table: cancer_related_genes_and_functionsIndexing rows in table: diane_drummond_awards_nominationsIndexing rows in table: diane_drummond_oscar_nominations_and_winsIndexing rows in table: diane_drummond_single_chart_performanceIndexing rows in table: euro_2020_group_stage_resultsIndexing rows in table: experiment_drop_events_timelineIndexing rows in table: filmography_of_diane_drummondIndexing rows in table: grammy_awards_summary_for_wilcoIndexing rows in table: historical_college_football_recordsIndexing rows in table: italian_ministers_term_datesIndexing rows in table: kodachrome_film_types_and_datesIndexing rows in table: missing_persons_case_summaryIndexing rows in table: monthly_climate_statisticsIndexing rows in table: monthly_climate_statistics_summaryIndexing rows in table: monthly_weather_statisticsIndexing rows in table: multilingual_greetings_and_phrasesIndexing rows in table: municipalities_merger_summaryIndexing rows in table: new_mexico_government_officialsIndexing rows in table: norwegian_club_performance_summaryIndexing rows in table: ohio_private_schools_summaryIndexing rows in table: progressive_rock_album_chart_positionsIndexing rows in table: regional_airports_usage_summaryIndexing rows in table: south_dakota_radio_stationsIndexing rows in table: triple_crown_winners_summaryIndexing rows in table: uk_ministers_and_titles_historyIndexing rows in table: voter_registration_status_by_partyIndexing rows in table: voter_registration_summary_by_partyIndexing rows in table: yamato_district_population_density我们扩展了表格解析功能,不仅返回相关的表格结构,还针对每个表格结构返回相关的数据行。
它现在同时接收 table_schema_objs(表格检索器的输出),以及原始的 query_str,后者将用于相关行的向量检索。
from llama_index.core.retrievers import SQLRetrieverfrom typing import List
sql_retriever = SQLRetriever(sql_database)
def get_table_context_and_rows_str( query_str: str, table_schema_objs: List[SQLTableSchema], verbose: bool = False,): """Get table context string.""" context_strs = [] for table_schema_obj in table_schema_objs: # first append table info + additional context table_info = sql_database.get_single_table_info( table_schema_obj.table_name ) if table_schema_obj.context_str: table_opt_context = " The table description is: " table_opt_context += table_schema_obj.context_str table_info += table_opt_context
# also lookup vector index to return relevant table rows vector_retriever = vector_index_dict[ table_schema_obj.table_name ].as_retriever(similarity_top_k=2) relevant_nodes = vector_retriever.retrieve(query_str) if len(relevant_nodes) > 0: table_row_context = "\nHere are some relevant example rows (values in the same order as columns above)\n" for node in relevant_nodes: table_row_context += str(node.get_content()) + "\n" table_info += table_row_context
if verbose: print(f"> Table Info: {table_info}")
context_strs.append(table_info) return "\n\n".join(context_strs)我们复用第1节中的工作流程,但在文本转SQL生成后增加了升级版的SQL解析步骤。
子类化和扩展现有工作流非常容易,并且可以自定义现有步骤以使其更高级。这里我们定义了一个新的工作流,它重写了现有的 retrieve_tables 步骤,以便返回相关的行。
from llama_index.core.workflow import ( Workflow, StartEvent, StopEvent, step, Context, Event,)
class TextToSQLWorkflow2(TextToSQLWorkflow1): """Text-to-SQL Workflow that does query-time row AND table retrieval."""
@step def retrieve_tables( self, ctx: Context, ev: StartEvent ) -> TableRetrieveEvent: """Retrieve tables.""" table_schema_objs = self.obj_retriever.retrieve(ev.query) table_context_str = get_table_context_and_rows_str( ev.query, table_schema_objs, verbose=self._verbose ) return TableRetrieveEvent( table_context_str=table_context_str, query=ev.query )由于整体步骤序列相同,图表看起来应该是一样的。
from llama_index.utils.workflow import draw_all_possible_flows
draw_all_possible_flows( TextToSQLWorkflow2, filename="text_to_sql_table_retrieval.html")text_to_sql_table_retrieval.html现在即使不完全匹配数据库中的条目,我们也可以查询相关条目。
workflow2 = TextToSQLWorkflow2( obj_retriever, text2sql_prompt, sql_retriever, response_synthesis_prompt, llm, verbose=True,)response = await workflow2.run( query="What was the year that The Notorious BIG was signed to Bad Boy?")print(str(response))Running step retrieve_tablesVERBOSE: True> Table Info: Table 'bad_boy_artists_album_release_summary' has columns: Act (VARCHAR), Year_signed (INTEGER), _Albums_released_under_Bad_Boy (VARCHAR), . The table description is: A summary of artists signed to Bad Boy Records along with the year they were signed and the number of albums they released.Here are some relevant example rows (values in the same order as columns above)('The Notorious B.I.G', 1993, '5')
> Table Info: Table 'filmography_of_diane_drummond' has columns: Year (INTEGER), Title (VARCHAR), Role (VARCHAR), Notes (VARCHAR), . The table description is: A list of film and television roles played by Diane Drummond from 1995 to 2001.Here are some relevant example rows (values in the same order as columns above)(2013, 'L.A. Slasher', 'The Actress', None)
> Table Info: Table 'progressive_rock_album_chart_positions' has columns: Year (INTEGER), Title (VARCHAR), Chart_Positions_UK (VARCHAR), Chart_Positions_US (VARCHAR), Chart_Positions_NL (VARCHAR), Comments (VARCHAR), . The table description is: Chart positions of progressive rock albums in the UK, US, and NL from 1969 to 1981.Here are some relevant example rows (values in the same order as columns above)(1977, 'Novella', '–', '46', '–', '1977 (January in US, August in UK, as the band moved to the Warner Bros Music Group)')
Step retrieve_tables produced event TableRetrieveEventRunning step generate_sqlStep generate_sql produced event TextToSQLEventRunning step generate_responseStep generate_response produced event StopEventassistant: The Notorious B.I.G. was signed to Bad Boy Records in 1993.