import polars as pl pl_data = pl.read_csv(data_file, has_header=False, new_columns=col_list) 运行apply函数,记录耗时: pl_data = pl_data.select([ pl.col(col).apply(lambda s: apply_md5(s)) for col in pl_data.columns ]) 查看运行结果: 3. Modin测试 Modin特点: 使用DataFrame作为基本...
一、Sqlite建表基本功:三大核心要素 1. 字段类型精要(新手必坑指南) # 常见字段类型及坑点 columns = [ ('id','INTEGER PRIMARY KEY AUTOINCREMENT'), # 自增主键 ('name','VARCHAR(50) NOT NULL'), # 必须非空 ('salary','DECIMAL(10,2) DEFAULT 0.00'), # 精确小数 ('created_at','TIMESTAMP...
<DF> = pd.read_sql('', <conn>) # Pass SQLite3/Alchemy connection (see #SQLite).<DF>.to_json/csv/html/parquet/latex(<path>) # Returns a string/bytes if path is omitted. <DF>.to_pickle/excel/feather/hdf(<path>) # To_hdf() requires `key='<df_name>'` argument. <DF>...
sqlite多线程并发写入python sqlsugar 多线程 前言 sqlsurgar自称是最简单,最高效的ORM框架。其他的暂且不考究,只有几百KB的大小可以说是非常轻量级的,昨日看了一下官方文档,使用确实方便。EF core作为官方的orm框架,据说在高并发查询下性能差强人意。尤其在一些小的项目上,引入EF core显得十分臃肿。这时采用SQLSugar应...
In SQLite3, the SELECT statement is executed in the execute method of the cursor object. For example, select all the columns of the employees’ table, run the following code: cursorObj.execute('SELECT * FROM employees ') If you want to select a few columns from a table, then specify th...
break except sqlite3.OperationalError as e: retries -= 1 time.sleep(5) if retries == 0: print(f"Failed to connect to {db_file} after multiple attempts") 2. 查询性能问题 原因:复杂的SQL查询或数据库表过大。 解决方案:优化SQL查询,使用索引,或分批处理数据。 代码语言:txt 复制 cursor.execute...
The export tab supports exporting all, or a subset, of columns: Basic INSERT, UPDATE and DELETE queries are supported: Command-line options The syntax for invoking sqlite-web is: $ sqlite_web [options] /path/to/database-file.db The following options are available: -p, --port: default is...
For example, the SQL query below would get all columns for all active records in some_table: SQL SELECT * FROM some_table WHERE active = 1; SQLite doesn’t have a Boolean data type, so the active column is represented by an integer with a value of 0 or 1 to indicate the state ...
Server 2016 (13.x) on a computer that isn't connected to the internet, the setup wizard might fail to display the prompt that lets you update the R components by using downloaded CAB files. This failure typically occurs when multiple components were installed together with...
The function will partition the query byevenlysplitting the specified column to the amount of partitions. ConnectorX will assign one thread for each partition to load and write data in parallel. Currently, we support partitioning onnumericalcolumns (cannot contain NULL) forSPJAqueries. ...