TCL(事务控制语言)语句:管理事务的开始、提交和回滚。 示例SQL脚本: sql -- SQL Script Example -- Step 1: Create a table called 'Employees' CREATE TABLE Employees ( EmployeeID INT PRIMARY KEY, FirstName VARCHAR(50), LastName VARCHAR(50), BirthDate DATE, Position VARCHAR(50) ); -- Step 2:...
SQL的核心功能包括数据定义语言(DDL)、数据操作语言(DML)、数据控制语言(DCL)和事务控制语言(TCL)。DDL用于定义数据库对象,例如表和索引;DML用于数据的插入、更新和删除;DCL用于控制对数据的访问权限;TCL用于管理事务的提交和回滚。 SQL的历史可以追溯到1970年代,由IBM的研究人员在开发System R数据库管理系统时首次提...
一、数据定义语言(DDL)1.创建数据库: CREATE DATABASE example_db; 2.删除数据库: DROP DATABASE example_db; 3.创建表: CREATE TABLE employees ( employee_id INT PRIMARY KEY,name VARCHAR (100) ,age INT,…
DROP DATABASE example_db; ``` 创建表: ```sql CREATE TABLE employees (employee_id INT PRIMARY KEY, name VARCHAR(100), age INT, department_id INT); ``` 删除表: ```sql DROP TABLE employees; ``` 添加列: ```sql ALTER TABLE employees ADD email VARCHAR(255); ``` 删除列: ```sql ...
TCL(Transaction Control Language) — managing changes safely Among these,queries, especially theSELECTcommand, are how you ask the database for information. Learning these basic commands is a crucial first step to working effectively with data in almost any software system. As you practice more, yo...
from langchain_core.prompts import FewShotPromptTemplate few_shot_prompt = FewShotPromptTemplate( example_selector=example_selector, example_prompt=example_prompt, prefix=( "Here are some examples of questions " "and their corresponding SQL queries." ), suffix=( "Question: {question}\n" "SQL...
example: SELECT * FROM Customers WHERE Country='Germany' AND (City='Berlin' OR City='München'); SQLORDER BY Keyword The ORDER BY keyword is used tosort the result-set(给结果集排序)by one or more columns. The ORDER BY keyword sorts the records in ascending orderby default. To sort the...
For example, Oracle and others include Java in the database, and SQL Server 2005 allows any .NET language to be hosted within the database server process, while PostgreSQL allows functions to be written in a wide variety of languages, including Perl, Tcl, and C.Extensions to and variations...
For example: mkdir bld cd bld nmake /f Makefile.msc TOP=..\sqlite nmake /f Makefile.msc sqlite3.c TOP=..\sqlite nmake /f Makefile.msc sqlite3.dll TOP=..\sqlite nmake /f Makefile.msc sqlite3.exe TOP=..\sqlite nmake /f Makefile.msc test TOP=..\sqlite ...
· QBE (Query By Example) created by Moshè Zloof, IBM 1977 · Quel introduced in 1974 by the U.C. Berkeley Ingres project. · Tutorial D · XQuery 应该区分作为语言的sql替代物和关系模型本身的替代方法。下面是sql语言中的关系式替代方案。见导航数据库和NoSQL对于关系模型的替代方法。 · n..QL...