app6.py
import dash import dash_html_components as html import dash_bootstrap_components as dbc import dash_core_components as dcc from dash.dependencies import Input, Output, State import pandas as pd from sqlalchemy import create_engine postgres_url = 'postgresql://postgres:填入你的密码@localhost:5432/Dash' engine = create_engine(postgres_url) app = dash.Dash(__name__) app.layout = html.Div( dbc.Container( [ dbc.Row( [ dbc.Col(dbc.Button('更新数据库信息',, style={'width': '100%'}), width=2), dbc.Col(dcc.Dropdown(id='db-table-names', placeholder='选择库中数据表', style={'width': '100%'}), width=4), dbc.Col(dbc.Button('查询',, style={'width': '100%'}), width=1) ] ), html.Hr(), dbc.Row( [ dbc.Col( ) ] ) ], style={ 'margin-top': '50px' # 设置顶部留白区域高度 } ) ) @app.callback( Output('db-table-names', 'options'), Input('refresh-db', 'n_clicks'), prevent_initial_call=True ) def query_data_records(n_clicks): # 提取目标表格并查询其最多前500行记录 table_names = pd.read_sql_query("select tablename from pg_tables where schemaname='public'", con=engine) return [{'label': name, 'value': name} for name in table_names['tablename']] @app.callback( Output('query-result', 'children'), Input('query', 'n_clicks'), State('db-table-names', 'value'), prevent_initial_call=True ) def refresh_table_names(n_clicks, value): if value: query_result = pd.read_sql_query(f'select * from {value} limit 500', con=engine) return html.Div(dbc.Table.from_dataframe(query_result, striped=True), style={'height': '600px', 'overflow': 'auto'}) else: return dash.no_update if __name__ == '__main__': app.run_server(debug=True)以上就是本文的全部内容，欢迎在评论区与我进行讨论~