upload SE305 数据库技术

README.md

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   - EI332 计算机组成
   - EI338 计算机系统工程
   - EI339 人工智能
+  - SE305 **数据库技术(进行中)**
 
 - 数学
   - MA357 数理统计
   - X071571 最优化方法
-  - MA26035 **测度与概率论** (**进行中**)
-  - X071565 **应用随机过程** (**进行中**)
+  - MA26035 **测度与概率论(进行中)**
+  - X071565 **应用随机过程(进行中)**
 
 ## 友情链接
 - [教学信息服务网](http://electsys.sjtu.edu.cn)

SE305 数据库技术(进行中)/Notes/Notes.md

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+## Course Overview
+
+- **Introduction** 
+- **Relational Model**
+- SQL
+  -  **introduction**
+  -  **intermediate**
+  -  advanced
+- Database Design and Application Design
+- Data Storage
+- Query Processing 
+- Transactions
+- Concurrency Control
+
+## 1 - Introduction
+- Levels of Abstraction
+  - physical level
+  - logical level
+  - view level
+- Schemas and Instances
+  - schema: logical structure
+  - instance: actual content
+- Data Models
+  - relational model
+  - entity-relationship data model
+  - object-based data model
+  - semi-structured data model (XML)
+- DML (data manipulation language)
+  - **declarative (nonprocedural)**: what to do 
+  - **procedural**: what to do + how to do
+- DDL (data definition language)
+
+## 2 - Relational Model
+- A relational database consists of a collection of tables, each of which is assigned a unique name.
+- In the relational model, the term **relation** is used to refer to a table, while the term **tuple** is used to refer to a row. Similarly, the term **attribute** refers to a column of a table.
+
+#### Structure
+- **tuple**: a tuple is a sequence (or list) of values
+- **relation**: a given sets $\{D_1, ..., D_n\}$, a relation $r$ is a **subset** of $D_1 \times \cdots \times D_n$.
+- **relation instance**: a specific instance of a relation, i.e., containing a specific set of rows.
+- **relation schema**
+  - eg. *department (dept name, building, budget)*
+  - eg. *teaches (ID, course id, sec id, semester, year)*
+<!--  - $r(R)$: a relation $r$ on $R$-->
+- **Database**: a database consists of multiple relations, where each relation stores one part of information
+- **Keys**
+  - attributes for $r$: $A_1, ..., A_n$
+  - $R = \{ A_1, ..., A_n \}$
+  - **superkey**: $K \subset R$ is a superkey for $r$ if $\forall t_1, t_2 \in r (t_1 \neq t_2)$ we have $t_1.K \neq t_2.K$
+  - **candidate key**: minimal superkey
+  - **primary key**: a candidate key that is chosen by the database designer as the principal means of identifying tuples within a relation.
+  - **foreign key**: a relation schema may have a set of attributes that corresponds to the primary key of another relation. These attributes is called a foreign key.
+- **Schema diagram**: ![](figures/schema_diagram.png)
+
+#### Basic Operations
+- select: $\sigma$
+  - $\sigma_p(r) = \{ t | t \in r ~and~ p(t)  \}$
+- project: $\Pi$
+- union: $\cup$
+  - conditions: same arity, compatible
+  - $r \cup s = \{ t | t \in r ~or~ t \in s \}$
+- set difference: $-$
+  - conditions: same arity, compatible
+  - $r - s = \{ t | t \in r ~and~ t \notin s \}$
+- Cartesian product: $\times$
+  - $r \times s = \{ t q | t \in r ~and~ q \in s \}$
+- rename: $\rho$
+
+#### Additional Operations
+- set intersection: $\cap$
+  - conditions: same arity, compatible
+  - $r \cap s = \{ t | t \in r ~and~ t \in s \}$
+  - $r \cap s = r-(r-s)$
+- natural join: $\bowtie$
+- division: $\div$
+- assignment: $\gets$
+
+#### Extended Operations
+- generalized projection
+  - Extends the projection operation by allowing arithmetic functions to be used in the projection list.
+  - $\Pi_{F_1, ..., F_n}(E)$
+  - $E$ is relational-algebra expression, and $F_i~(1\leq 1\leq n)$ are arithmetic expressions.
+- aggregate functions
+  - avg, min, max, sum, count
+  - $_{G_1, ..., G_n} g _{F_1(A_1), ..., F_n(A_n)} (E)$
+- outer join
+  - an extension of the join operation that avoids loss of information.
+  - left outer join: $$
+  - right outer join
+  - full outer join
+
+### Null
+- null signifies an unknown value or that a value does not exist
+
+### Modification of the Database
+ - deletion: $r \gets r - E$
+ - insertion: $r \gets r \cup E$
+ - update: $r \gets \Pi_{F_1, ..., F_n} (r)$
+
+## 3, 4, 5 - Intro to SQL (I)(II)(III)
+
+<!--### Data Definition -->
+
+### Basics
+- Domain Types in SQL
+  - char(n)
+  - varchar(n)
+  - int
+  - smallint
+  - numeric(p, d)
+  - real, double precision
+  - float(n)
+- Create Table Construct
+  - **create table** r ($A_1, D_1, ..., A_n, D_n$, integrity-constraints)
+  - r: name of relation
+  - $A_i~(1 \leq i \leq n)$: attribute name
+  - $D_i~(1 \leq i \leq n)$: data type of $A_i$
+- Integrity constrains
+  -  not null
+  -  primary key $(A_1, ..., A_n)$
+  -  foreign key $(A_i, ..., A_n)$ references r
+
+### Basic Query Structure
+- **select** $A_1, ..., A_n$ **from** $r_1, ..., r_n$ **where** $P$
+  - $A_1, ..., A_n$: attributes
+  - $r_1, ..., r_n$: relation
+  - $P$: predicate
+- **select**: generalized projection $\Pi$
+  - ***SQL allows duplicates in relations as well as in query results***
+  - **select distinct**: remove duplicates
+  - **select all**: don't remove duplicates
+  - **select \***: select all attributes
+- **from**: Cartesian product $\times$
+- **where**: selection $\sigma$
+
+### Additional Basic Operations
+- **natural join**
+- rename: **as**
+- string operation: **like**
+  - % matches any substring
+  - _ matches any character
+- Ordering the Display of Tuples: **order by** $A_i$ **asc/desc**
+- duplicate
+
+### Set Operations
+- union
+- intersect
+- except
+
+### Null Values
+
+### Aggerate Functions
+
+### Nested Subqueries
+
+### Modification of the Database
+
+### Join Expressions
+
+### Views
+
+### Transactions
+
+### Integrity Constraints
+
+### SQL Data Types and Schemas
+
+### Authorization
+
+### Embedded SQL
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SE305 数据库技术(进行中)/Readme.md

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+- 讲师: 朱其立
+- 学分: 3
+- 学期: 大四上
+- 网站: http://www.cs.sjtu.edu.cn/~kzhu/se305/