PostgreSQL

• 4. SQL Syntax

  • 4.1. Lexical Structure
  • 4.2. Value Expressions | type cast

• 5. Data Definition

  • 5.1. Table Basics
  • 5.2. Default Values
  • 5.3. Constraints
  • 5.5. Modifying Tables
  • 5.7. Schemas
  • 5.9. Table Partitioning | insert | query
  • 5.10. Other Database Objects
  • 5.11. Dependency Tracking

• 6. Data Manipulation

  • 6.1. Inserting Data
  • 6.2. Updating Data
  • 6.3. Deleting Data
  • 6.4. Returning Data From Modified Rows

• 7. Queries

  • 7.1. Overview | parser | analyser | rewriter | planner | executor
  • 7.2. Table Expressions
  • 7.3. Select Lists
  • 7.4. Combining Queries
  • 7.5. Sorting Rows
  • 7.6. LIMIT and OFFSET
  • 7.7. VALUES Lists
  • 7.8. WITH Queries (Common Table Expressions)
  • 7.9. Joins ｜ cross join 无on| inner join 有 on | left join left为主｜ right join为主

• 8. Data Types

  • 8.1. Numeric Types | int2,int4,int8 | real,double precision | smallserial, serial, bigserial
  • 8.2. Monetary Types
  • 8.3. Character Types | varchar | char | text
  • 8.4. Binary Data Types
  • 8.5. Date/Time Types
  • 8.6. Boolean Type | true | yes | on | 1
  • 8.7. Enumerated Types | order | type safety
  • 8.8. Geometric Types | point | lines | boxes | polygons | circle
  • 8.9. Network Address Types
  • 8.10. Bit String Types todo
  • 8.11. Text Search Types todo
  • 8.12. UUID Type
  • 8.13. XML Type todo
  • 8.14. JSON Types | input output syntax | reparse
  • 8.14. JSONB Types | binary | gin indexing
  • 8.15. Arrays | input output syntax | accessing | modify | search
  • 8.16. Composite Types
  • 8.17. Range Types | input output syntax | GiST and SP-GiST index
  • 8.18. Domain Types todo
  • 8.19. Object Identifier Types todo
  • 8.20. pg_lsn Type todo
  • 8.21. Pseudo-Types todo

• 9. Functions and Operators

  • 9.1. Logical Operators
  • 9.2. Comparison Functions and Operators
  • 9.3. Mathematical Functions and Operators
  • 9.4. String Functions and Operators
  • 9.5. Binary String Functions and Operators
  • 9.6. Bit String Functions and Operators
  • 9.7. Pattern Matching
  • 9.8. Data Type Formatting Functions
  • 9.9. Date/Time Functions and Operators
  • 9.10. Enum Support Functions
  • 9.11. Geometric Functions and Operators
  • 9.12. Network Address Functions and Operators
  • 9.13. Text Search Functions and Operators
  • 9.14. XML Functions
  • 9.15. JSON Functions and Operators
  • 9.16. Sequence Manipulation Functions
  • 9.17. Conditional Expressions
  • 9.18. Array Functions and Operators
  • 9.19. Range Functions and Operators
  • 9.20. Aggregate Functions
  • 9.21. Window Functions
  • 9.22. Subquery Expressions
  • 9.23. Row and Array Comparisons
  • 9.24. Set Returning Functions
  • 9.25. System Information Functions and Operators
  • 9.26. System Administration Functions
  • 9.27. Trigger Functions
  • 9.28. Event Trigger Functions
  • 9.29. Statistics Information Functions

• 10. Type Conversion

  • 10.1. Overview
  • 10.2. Operators
  • 10.3. Functions
  • 10.4. Value Storage
  • 10.5. UNION, CASE, and Related Constructs

• 11. Indexes

  • 11.1. Introduction

  • 11.2. Index Types

    • Hash
    • Btree
    • GiST | B+ tree | generalized search tree
    • SP-GiST | space generalized search tree
    • GIN | Generalized Inverted Index
    • RUM | BRIN

  • 11.3. Multicolumn Indexes

  • 11.4. Indexes and ORDER BY

  • 11.5. Combining Multiple Indexes

  • 11.6. Unique Indexes

  • 11.7. Indexes on Expressions

  • 11.8. Partial Indexes

  • 11.9. Index-Only Scans and Covering Indexes

    • Index only scan, 最优， select， where , order 都命中index
    • Index scan, 第二， where, order命中index
    • Partial Index Scan，也是index scan， where, order命中index, 且match the partial index condition
    • bitmap heap scan, bitmap index scan, 以下情况都走bitmap index scan
      • "where分开命中2个index"
      • "相同index但是是or条件"
      • "查询的数据大于pg_relation_size"
    • sequential scan , 没命中index
    • backward_scan
    • Nested Loops join, 命中index, 且是limit数据 | sql
    • Hash join, 没有命中index时， 或者无limit，全表join时 | sql
    • Merge join, 有order by时 | sql

  • 11.10. Operator Classes and Operator Families

  • 11.11. Indexes and Collations

  • 11.12. Examining Index Usage

  • Index Obfuscation

• 12. Full Text Search

  • 12.1. Introduction
  • 12.2. Tables and Indexes
  • 12.3. Controlling Text Search
  • 12.4. Additional Features
  • 12.5. Parsers
  • 12.6. Dictionaries
  • 12.7. Configuration Example
  • 12.8. Testing and Debugging Text Search
  • 12.9. GIN and GiST Index Types
  • 12.10. psql Support
  • 12.11. Limitations

• 13. Concurrency Control

  • 13.1. Introduction | Multiversion Concurrency Control, MVCC | locks | read not conflict write
  • 13.2. Transaction Isolation | read commit | repeatable read | serializable
  • 13.3. Explicit Locking | table-level lock | row-level lock | page-level lock | deadlocks | advisory locks
  • 13.4. Data Consistency Checks at the Application Level
  • 13.5. Caveats
  • 13.6. Locking and Indexes | page-level locks
  • 13.7. ACID | atomicity | consistency | isolation | durability

• 14. Performance Tips

  • 14.1. Using EXPLAIN
    • cost - the first value represents the cost at which the node begins execution, while the second value is the estimated cost for when the execution is done
    • rows - the estimated number of rows the node will produce.
    • width - the estimated average row size in bytes for the current node.
    • actual time - similar to the cost attribute, but represents the execution time in seconds
    • rows - the actual number of rows that the node produced.
    • loops - the number of times a node got executed
  • 14.2. Statistics Used by the Planner
  • 14.3. Controlling the Planner with Explicit JOIN Clauses
  • 14.4. Populating a Database | copy | prepare execute| Remove Indexes then Recreate indexes| create index in existing data | Remove Foreign Key Constraints
  • 14.5. Non-Durable Settings

• Internal

  • Database Cluster, Databases and Tables
  • Process and Memory Architecture
  • Query Processing
  • Foreign Data Wrappers (FDW) and Parallel Query
  • Concurrency Control
  • VACUUM Processing
  • Heap Only Tuple (HOT) and Index-Only Scans
  • Buffer Manager
  • Write Ahead Logging (WAL)
  • Base Backup and Point-In-Time Recovery (PITR)
  • Streaming Replication

• I. SQL Commands

  • ALTER TABLE — change the definition of a table
  • ALTER TYPE — change the definition of a type
  • CREATE FOREIGN DATA WRAPPER — define a new foreign-data wrapper
  • CREATE FOREIGN TABLE — define a new foreign table
  • CREATE FUNCTION — define a new function
  • CREATE GROUP — define a new database role
  • CREATE INDEX — define a new index
  • CREATE TABLE — define a new table
  • CREATE TABLE AS — define a new table from the results of a query
  • CREATE TRANSFORM — define a new transform
  • CREATE TRIGGER — define a new trigger
  • CREATE TYPE — define a new data type
  • CREATE USER — define a new database role
  • CREATE USER MAPPING — define a new mapping of a user to a foreign server
  • CREATE VIEW — define a new view
  • VALUES — compute a set of rows

MySQL

• 1 General Information | SQL Syntax

  • [1.2 Typographical and Syntax Conventions
    • () , 一组
    • [] , options
    • | , 枚举， 选一
    • {}， 多选
  • 1.8 MySQL Standards Compliance | extensions | difference | constraints
  • 1.8.1 MySQL Standards Compliance extensions
  • 1.8.2 MySQL Standards Compliance difference
  • 1.8.2 MySQL Standards Compliance constraints

• 9 Language Structure

  • 9.1 Literal Values | string | numeric | data time | boolean
  • 9.2 Schema Object Names

• 11 Data Types

  • 11.1 Numeric Data Types INTEGER, INT, SMALLINT, TINYINT, MEDIUMINT, BIGINT | Fixed-Point Types |Floating-Point Types
  • 11.2 Date and Time Data Types | DATETIME, and TIMESTAMP Types
  • 11.3 String Data Types | char | varchar | text | enum | set
  • 11.4 Spatial Data Types |Geometry Model
  • 11.5 The JSON Data Type
  • 11.6 Data Type Default Values
  • 11.7 Data Type Storage Requirements
  • 11.8 Choosing the Right Type for a Column
  • 11.9 Using Data Types from Other Database Engines

• 13 SQL Statements

  • 13.1 Data Definition Statements
    • database | table
    • index
    • trigger | view
    • server | spatial ｜event
    • function | instance
  • 13.2 Data Manipulation Statements
    • insert | update | delete | select
    • do | import | table |values | with
  • 13.3 Transactional and Locking Statements
    • START TRANSACTION, COMMIT, and ROLLBACK | savepoint
  • 13.4 Replication Statements
    • master | slave | group replication
  • 13.5 Prepared Statements
    • prepare | execute | deallocate | compound | begin ... end | flow control | cursors
  • 13.7 Database Administration Statements
    • clone | set | show | describe | explain | help | use

• 7. Queries - join | full | inner or cross | left | right - join optimizing | inner | outer | semi | anti
  

• Optimizing

  • 8.2 Optimizing SQL Statements
    • 8.2.1 Optimizing SELECT Statements | where 易读，避免全表扫 | range
    • 8.2.1 Optimizing SELECT Statements | Index lookup | Index Range Scan | Inner hash join | Nested loop inner join
    • 8.2.2 Optimizing Subqueries, Derived Tables, View References, and Common Table Expressions
    • 8.2.3 Optimizing INFORMATION_SCHEMA Queries
    • 8.2.4 Optimizing Performance Schema Queries
    • 8.2.5 Optimizing Data Change Statements
    • 8.2.6 Optimizing Database Privileges
    • 8.2.7 Other Optimization Tips
  • 8.3 Optimization Indexes
    • 8.3.1 How MySQL Uses Indexes | leftmost prefix |
      • B-trees(PRIMARY KEY, UNIQUE, INDEX, and FULLTEXT)
      • R-trees(spatial data types)
    • 8.3.2 Primary Key Optimization
    • 8.3.3 SPATIAL Index Optimization
    • 8.3.4 Foreign Key Optimization
    • 8.3.5 Column Indexes
    • 8.3.6 Multiple-Column Indexes
    • 8.3.7 Verifying Index Usage
    • 8.3.8 InnoDB and MyISAM Index Statistics Collection
    • 8.3.9 Comparison of B-Tree and Hash Indexes
    • 8.3.10 Use of Index Extensions
    • 8.3.11 Optimizer Use of Generated Column Indexes
    • 8.3.12 Invisible Indexes
    • 8.3.13 Descending Indexes
    • 8.3.14 Indexed Lookups from TIMESTAMP Columns
  • 8.4 Optimizing Database Structure | data size | data type | table size | row size
  • 8.5 Optimizing for InnoDB Tables
  • 8.6 Optimizing for MyISAM Tables
  • 8.8 Query Execution Plan
  • 8.9 Controlling the Query Optimizer | optimizer hints | index hints | cost
  • 8.10 Buffering and Caching
  • 8.11 Optimizing Locking Operations | internal lock | table lock | metadata lock | external lock

• 12 Functions and Operators

  • 12.1 Function and Operator Reference
  • 12.2 Type Conversion in Expression Evaluation
  • 12.3 Operators | logical | comparison
  • 12.4 Control Flow Functions
  • 12.5 Numeric Functions and Operators
  • 12.6 Date and Time Functions
  • 12.7 String Functions and Operators
  • 12.8 What Calendar Is Used By MySQL?
  • 12.9 Full-Text Search Functions
  • 12.10 Cast Functions and Operators
  • 12.11 XML Functions
  • 12.12 Bit Functions and Operators
  • 12.13 Encryption and Compression Functions
  • 12.14 Locking Functions
  • 12.15 Information Functions
  • 12.16 Spatial Analysis Functions
  • 12.17 JSON Functions
  • 12.20 Aggregate (GROUP BY) Functions
  • 12.21 Window Functions
  • 12.22 Performance Schema Functions
  • 12.23 Internal Functions

• 24 Stored Objects

  • 24.2 Using Stored Routines
  • 24.2.4 Stored Procedures, Functions, Triggers, and LAST_INSERT_ID()
  • 24.3 Using Triggers
  • 24.5 Using Views
  • 24.6 Stored Object Access Control
  • 24.7 Stored Program Binary Logging
  • 24.8 Restrictions on Stored Programs
  • 24.9 Restrictions on Views

• 17 Replication

  • 17.1 Configuring Replication
  • 17.2 Replication Implementation
  • 17.3 Replication Security
  • 17.4 Replication Solutions
  • 17.5 Replication Notes and Tips

• 23 Partitioning

  • 23.1 Overview of Partitioning in MySQL
  • 23.2 Partitioning Types
  • 23.3 Partition Management
  • 23.4 Partition Pruning
  • 23.5 Partition Selection
  • 23.6 Restrictions and Limitations on Partitioning

• 4 MySQL Programs

  • 4.5.1 mysql — The MySQL Command-Line Client
  • 4.5.2 mysqladmin — Client for Administering a MySQL Server
  • 4.5.3 mysqlcheck — A Table Maintenance Program
  • 4.5.4 mysqldump — A Database Backup Program
  • 4.5.5 mysqlimport — A Data Import Program
  • 4.5.6 mysqlpump — A Database Backup Program
  • 4.5.7 mysqlshow — Display Database, Table, and Column Information
  • 4.5.8 mysqlslap — Load Emulation Client

MongoDB

redis

• string
• lists
• sets
• sorted sets
• hashes
• transaction | code
• replication
• persistence | RDB | AOF