You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
116 lines
2.2 KiB
116 lines
2.2 KiB
# PostGres - Advanced
|
|
|
|
## Lesson Objectives - important
|
|
|
|
1. Linking Tables
|
|
1. Alias
|
|
1. Indexes
|
|
1. Constraints
|
|
1. Distinct
|
|
|
|
## Lesson Objectives - good to know about
|
|
|
|
1. EER Diagrams
|
|
1. Unions
|
|
1. Truncate
|
|
1. Triggers
|
|
1. Views
|
|
1. Functions/Stored Procedures
|
|
1. Transactions
|
|
1. Locks
|
|
1. Privileges
|
|
1. Denormalization
|
|
1. Excel -> CSV -> MySQL
|
|
|
|
## Important
|
|
|
|
### Linking Tables
|
|
|
|
1. [Some Nice Visuals](http://code.tutsplus.com/articles/sql-for-beginners-part-3-database-relationships--net-8561)
|
|
1. One to Many/Many to One Relationships
|
|
- customer has many orders
|
|
1. One to One Relationships
|
|
- each user has one address
|
|
- only one person at that address
|
|
1. Many to Many Relationships
|
|
- actors and movies
|
|
1. Self Referncing Relationships
|
|
- customer referral
|
|
|
|
### Alias
|
|
|
|
```sql
|
|
SELECT t1.column1 as col1, t2.column2 as col2
|
|
FROM table1 as t1
|
|
INNER JOIN table2 as t2
|
|
ON t1.common_filed = t2.common_field;
|
|
```
|
|
|
|
### Indexes
|
|
|
|
1. `CREATE INDEX index_name ON table_name (column_name);`
|
|
1. `CREATE INDEX index_name ON table_name (column1_name, column2_name);`
|
|
1. use `\d table_name` to view indexes
|
|
1. Primary Key
|
|
|
|
### Constraints
|
|
|
|
1. NOT NULL
|
|
1. Unique
|
|
1. Foreign Keys
|
|
|
|
```sql
|
|
CREATE TABLE companies(
|
|
id SERIAL PRIMARY KEY,
|
|
name VARCHAR(16) NOT NULL UNIQUE,
|
|
city VARCHAR(16)
|
|
);
|
|
INSERT INTO companies ( city ) VALUES ('Palo Alto');
|
|
CREATE TABLE people(
|
|
id INT PRIMARY KEY,
|
|
name VARCHAR(16) NOT NULL,
|
|
email VARCHAR(32) NOT NULL UNIQUE,
|
|
company_id INT REFERENCES companies(id)
|
|
);
|
|
INSERT INTO people (name, email, company_id) VALUES ('bob', 'bob@bob.com', 999)
|
|
```
|
|
|
|
### Distinct
|
|
|
|
```sql
|
|
SELECT DISTINCT city FROM people;
|
|
```
|
|
|
|
## Good to Know About
|
|
|
|
### EER Diagrams
|
|
|
|
|
|
|
|
### Unions
|
|
|
|
```sql
|
|
SELECT name FROM people UNION SELECT name FROM companies; -- show distinct values
|
|
SELECT name FROM people UNION ALL SELECT name FROM companies; -- show duplicates
|
|
```
|
|
|
|
### Truncate
|
|
|
|
### Triggers
|
|
|
|
### Views
|
|
|
|
### Functions/Stored Procedures
|
|
|
|
### Transactions
|
|
|
|
### Locks
|
|
|
|
### Privileges
|
|
|
|
### Denormalization
|
|
|
|
### Excel -> CSV -> MySQL
|
|
|
|
### SQL Injection
|