0%

数据库常用关系代数符号在 LaTeX 中的表示

Relational Algebra / 关系代数符号可以用于表达数据库标准操作逻辑。近期做数据库作业时经常需要用 \(\LaTeX\) 表示关系代数的符号,故在这里稍作整理。

Operation中文符号\(\LaTeX\)
Projection投影\(\Pi\)\Pi
Selection选择\(\sigma\)\sigma
Renaming重命名\(\rho\)\rho
Aggregate Function聚合函数\(\mathcal{G}\)\mathcal{G}
Union\(\cap\)\cap
Intersection\(\cup\)\cup
Natural Join自然连接\(\bowtie\)\bowtie
Left Outer Join左外连接... 这几个直接复制吧
Right Outer Join右外连接
Full Outer Join全外连接
Cartesian product笛卡尔乘积\(\times\)\times
Divide\(\div\)\div
Assignment赋值\(\leftarrow\)\leftarrow
And条件并列\(\land\)\land or \vee
Negation\(\neg\)\neg
Exist存在\(\exists\)\exists
For All对所有\(\forall\)\forall
下标文字\(\sigma_{\text{username}}\)_{\text{}}
粗体文字\(\mathcal{G}_{\textbf{count(*)}}\)\textbf{}
长长长长括号\(\big( \Big( \bigg( \Bigg(\)\big( \Big( \bigg( \Bigg(
比较\(\gt \ge \lt \le \ne\)\gt \ge \lt \le \ne

一个栗子🌰:

1
2
3
c\leftarrow \Pi_{count}\Big(\sigma_{\text{publisher="McGraw-Hill"}}(_{publisher,} \mathcal{G}_{\textbf{count(*) as count}}(books))\Big) \\
t\leftarrow _{name,}\mathcal{G}_{\textbf{count(*) as memcount}}(\sigma_{\text{publisher="McGraw-Hill"}}(member \bowtie borrowed\bowtie books)) \\
\Pi_{name}(\sigma_{\text{memcount=c}}(t))

\[c\leftarrow \Pi_{count}\Big(\sigma_{\text{publisher='McGraw-Hill'}}(_{publisher,} \mathcal{G}_{\textbf{count(*) as count}}(books))\Big)\]

\[t\leftarrow _{name,}\mathcal{G}_{\textbf{count(*) as memcount}}(\sigma_{\text{publisher='McGraw-Hill'}}(member \bowtie borrowed\bowtie books))\]

\[\Pi_{name}(\sigma_{\text{memcount=c}}(t))\]

Welcome to my other publishing channels