General outline for the first day of learning python

1). Python basic grammar: 4 weeks course(Final exam)2).Front-end knowledge points: html, css, javascript(js)、jQuery

3). Linux(system),database(Relational&非Relational)4).python framework

5). reptile

6). data analysis(artificial intelligence)database(database：db)

Definition: A warehouse that stores data

Main object: data sheet(table)

Common database objects: tables, views, indexes, sequences, synonyms...Table structure: Row(row), Column(column)Row: a piece of data(information)Column: field(单独的information数据)

sql：structure query language(Structured query language)

classification:

1). DDL operation:(Tough, equivalent to the CEO in the enterprise)For operating database objects(form)The level:

contain:

①.Create a table: create table...

②.Drop table: drop table...

③.Modify table(increase/delete/Modify a column)：alter table ...

④.Empty table: truncate table...

Features:

Submit by default, no regrets(Not allowed to return)2).DML operation:(Gentle, equivalent to a project manager in an enterprise)

For the data level:

contain:

①.Increase data: insert into...

②.Delete data: delete...

③.Modify data: update...

④.Query data: select...

Features:

Will not submit by default, you can roll back(Regret taking medicine)Web programmer mantra: crud operation(Add, delete, modify)3).DCL operation:

For the processing of some things:

contain:

①.Submit operation: commit

②.Rollback operation: rollback

Data types in oracle:

1). Number: number

Division:

①.Integer type:

Variable m: indicates the length

number(m)-->Example: number(5)1000(Correct)、20000(Correct)、0(Correct)、999999(wrong)

②.Floating point:

Variable m:Indicates the overall length

Variable n: how many decimal places

number(m,n)-->Example: number(8,3)1234.567(Correct)、123.23(Correct)、666666.666(wrong)2).Character type:

Variable m: indicates the length

Division:

①.Fixed-length characters:

char(m)：-->Example: char(3)gender(male/m/0, female/f/1)

②.Variable length characters:

varchar2(m)：-->Example: char(30)Sex name: Invincible in the East, Ouyang Zhenhua

Distinguish between fixed-length and variable-length characters:

For variable-length characters, if the data is not full, the bottom layer of the database will automatically save the remaining capacity, but the retrieval efficiency is relatively slow(Equivalent to definition)For fixed-length characters, if the data is not full, the bottom layer of the database will still use the excess capacity(waste), But the retrieval efficiency is faster(Equivalent to variable length)3).Date type:

Keyword: date

Create table for DDL operation:

format:

create table table name(

Column name 1 data type 1(length),

Column name 2 data type 2(length),...

Column name n data type n(length));

Precautions:

1). All punctuation marks must be in the English input method

2). We cannot duplicate the table name,Do not use Chinese names

3). The semicolon can be omitted after the last column name

demand:

Create our first table: table name(python1808_your name)

Designed columns and types&The length is as follows:

Column name type&length

Name(name)varchar2(30)age(age)number(3)gender(sex)char(2)Date of birth(birthday)date

Graduated school(school)varchar2(25)

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