CREATE TABLE [IF NOT EXISTS] `表名`( '字段名' 列类型 [属性] [索引] [注释], '字段名' 列类型 [属性] [索引] [注释], ... '字段名' 列类型 [属性] [索引] [注释] ) 1. 2. 3. 4. 5. 索引和注释可选择性加入 CREATE TABLE bank( b_id CHAR(5) PRIMARY KEY , b_name VARCHAR(30...
CREATE TABLE(创建表) *语法: CREATE TABLE [IF NOT EXISTS] table_name ( 列名 数据类型 列级约束, ……, 表级约束 ); *创建表时,需要指定下列内容: 1、唯一的表名称; 2、表内唯一的列名称; 3、列的数据类型及其宽度; 1. 2. 3. 4. 2、数据类型。 (1)字符数据类型 CHAR[(M)] 一个定长字符串...
SqlAlchemy already supports these operations on DropTable and CreateTable so this would essentially be a pass-through in a similar manner. Databases / Backends / Drivers targeted Postgresql Example Use Much like drop_index, I'd expect op.drop_table('foobar', if_exists=True) to produce DROP ...
from sqlalchemyimportcreate_engine#1 准备#需要事先安装好pymysql#需要事先创建好数据库:create database db1 charset utf8;#2 创建引擎 egine=create_engine('mysql+pymysql://root@127.0.0.1/db1?charset=utf8')#3 执行sql#egine.execute('create table if not EXISTS t1(id int PRIMARY KEY auto_incr...
CREATE TABLE IF NOT EXISTS `job` ( `id` INT NOT NULL AUTO_INCREMENT, `job_status` INT NOT NULL, `job_name` VARCHAR(255), PRIMARY KEY (`id`) )ENGINE=InnoDB DEFAULT CHARSET=utf8mb4; 数据操作 SQLAlchemy对数据库的操作都是通过Session进行的,Session的创建在 创建连接&&Session 部分,Session的...
I need to create wordpress databases using mysqldb connected to a mysql server but using the SQLAlchemy code. The SQL for the table is as follows: CREATE TABLE IF NOT EXISTS `wp_links` ( `link_id` bigint(20) unsigned NOT NULL auto_increment, `link_url` varchar(255) NOT NULL ...
Added support for :paramref:`.Operations.create_table.if_not_exists` and :paramref:`.Operations.drop_table.if_exists`, adding similar functionality to render IF [NOT] EXISTS for table operations in a similar way as with indexes. Pull request courtesy Aaron Griffin. Fixes: #1520 Closes: #1521...
from sqlalchemy import create_engine #1 准备 # 需要事先安装好pymysql # 需要事先创建好数据库:create database db1 charset utf8; #2 创建引擎 egine=create_engine('mysql+pymysql://root@127.0.0.1/db1?charset=utf8') #3 执行sql # egine.execute('create table if not EXISTS t1(id int PRIMA...
pool_recycle=60, pool_pre_ping=True)#判断写入的数据库是否存在ifnotdatabase_exists(engine.url): create_database(engine.url)#创建ORM对象的基类,用于后续创建class类Base =declarative_base() #创建metadate对象,关联engine使用metadata创建数据库表metadata =MetaData(engine)#定义session会话对象,创建一个会话,...
(String) engine = create_engine('sqlite:///:memory:') Base.metadata.create_all(engine) Session = sessionmaker(bind=engine) session = Session() # 假设我们有一个查询 query = session.query(User).filter(User.name == 'John') # 检查查询结果是否为空 if query.count() == 0: print("...