PostgreSQL 正體中文使用手冊
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  • 簡介
  • 前言
    • 1. 什麼是 PostgreSQL?
    • 2. PostgreSQL 沿革
    • 3. 慣例
    • 4. 其他參考資訊
    • 5. 問題回報指南
  • I. 新手教學
    • 1. 入門指南
      • 1.1. 安裝
      • 1.2. 基礎架構
      • 1.3. 建立一個資料庫
      • 1.4. 存取一個資料庫
    • 2. SQL 查詢語言
      • 2.1. 簡介
      • 2.2. 概念
      • 2.3. 創建一個新的資料表
      • 2.4. 資料列是資料表的組成單位
      • 2.5. 資料表的查詢
      • 2.6. 交叉查詢
      • 2.7. 彙總查詢
      • 2.8. 更新資料
      • 2.9. 刪除資料
    • 3. 先進功能
      • 3.1. 簡介
      • 3.2. 檢視表(View)
      • 3.3. 外部索引鍵
      • 3.4. 交易安全
      • 3.5. 窗函數
      • 3.6. 繼承
      • 3.7. 結論
  • II. SQL 查詢語言
    • 4. SQL 語法
      • 4.1. 語法結構
      • 4.2. 參數表示式
      • 4.3. 函數呼叫
    • 5. 定義資料結構
      • 5.1. 認識資料表
      • 5.2. 預設值
      • 5.3. Generated Columns
      • 5.4. 限制條件
      • 5.5. 系統欄位
      • 5.6. 表格變更
      • 5.7. 權限
      • 5.8. 資料列安全原則
      • 5.9. Schemas
      • 5.10. 繼承
      • 5.11. 分割資料表
      • 5.12. 外部資料
      • 5.13. 其他資料庫物件
      • 5.14. 相依性追蹤
    • 6. 資料處理
      • 6.1. 新增資料
      • 6.2. 更新資料
      • 6.3. 刪除資料
      • 6.4. 修改並回傳資料
    • 7. 資料查詢
      • 7.1. 概觀
      • 7.2. 資料表表示式
      • 7.3. 取得資料列表
      • 7.4. 合併查詢結果
      • 7.5. 資料排序
      • 7.6. LIMIT 和 OFFSET
      • 7.7. VALUES 列舉資料
      • 7.8. WITH Querys(Common Table Expressions)
    • 8. 資料型別
      • 8.1. 數字型別
      • 8.2. 貨幣型別
      • 8.3. 字串型別
      • 8.4. 位元組型別(bytea)
      • 8.5. 日期時間型別
      • 8.6. 布林型別
      • 8.7. 列舉型別
      • 8.8. 地理資訊型別
      • 8.9. 網路資訊型別
      • 8.10. 位元字串型別
      • 8.11. 全文檢索型別
      • 8.12. UUID 型別
      • 8.13. XML 型別
      • 8.14. JSON 型別
      • 8.15. 陣列
      • 8.16. 複合型別
      • 8.17. 範圍型別
      • 8.18. Domain Types
      • 8.19. 物件指標型別
      • 8.20. pg_lsn 型別
      • 8.21. 概念型別
    • 9. 函式及運算子
      • 9.1. 邏輯運算子
      • 9.2. 比較函式及運算子
      • 9.3. 數學函式及運算子
      • 9.4. 字串函式及運算子
      • 9.5. 位元字串函式及運算子
      • 9.6. 二元字串函式及運算子
      • 9.7. 特徵比對
      • 9.8. 型別轉換函式
      • 9.9 日期時間函式及運算子
      • 9.10. 列舉型別函式
      • 9.11. 地理資訊函式及運算子
      • 9.12. 網路位址函式及運算子
      • 9.13. 文字檢索函式及運算子
      • 9.14. UUID Functions
      • 9.15. XML 函式
      • 9.16. JSON 函式及運算子
      • 9.17. 序列函式
      • 9.18. 條件表示式
      • 9.19. 陣列函式及運算子
      • 9.20. 範圍函式及運算子
      • 9.21. 彙總函數
      • 9.22. Window 函式
      • 9.23. 子查詢
      • 9.24. 資料列與陣列的比較運算
      • 9.25. 集合回傳函數
      • 9.26. 系統資訊函數
      • 9.27. 系統管理函式
      • 9.28. 觸發函式
      • 9.29. 事件觸發函式
      • 9.30. Statistics Information Functions
    • 10. 型別轉換
      • 10.1. 概觀
      • 10.2. 運算子
      • 10.3. 函式
      • 10.4. 資料儲存轉換規則
      • 10.5. UNION、CASE 等相關結構
      • 10.6. SELECT 輸出規則
    • 11. 索引(Index)
      • 11.1. 簡介
      • 11.2. 索引型別
      • 11.3. 多欄位索引
      • 11.4. 索引與 ORDER BY
      • 11.5. 善用多個索引
      • 11.6. 唯一值索引
      • 11.7. 表示式索引
      • 11.8. 部份索引(partial index)
      • 11.9. Index-Only Scans and Covering Indexes
      • 11.10. 運算子物件及家族
      • 11.11. 索引與排序規則
      • 11.12. 檢查索引運用
    • 12. 全文檢索
      • 12.1. 簡介
      • 12.2. 查詢與索引
      • 12.3. 細部控制
      • 12.4. 延伸功能
      • 12.5. 斷詞
      • 12.6. 字典
      • 12.7. 組態範例
      • 12.8. 測試與除錯
      • 12.9. GIN 及 GiST 索引型別
      • 12.10. psql支援
      • 12.11. 功能限制
    • 13. 一致性管理(Concurrency Control)
      • 13.1. 簡介
      • 13.2. 交易隔離
      • 13.3. 鎖定模式
      • 13.4. 在應用端檢視資料一致性
      • 13.5. Serialization Failure Handling
      • 13.6. 特別提醒
      • 13.7. 鎖定與索引
    • 14. 效能技巧
      • 14.1. 善用 EXPLAIN
      • 14.2. 統計資訊
      • 14.3. 使用確切的 JOIN 方式
      • 14.4. 快速建立資料庫內容
      • 14.5. 風險性彈性設定
    • 15. 平行查詢
      • 15.1. 如何運作?
      • 15.2. 啓用時機?
      • 15.3. 平行查詢計畫
      • 15.4. 平行查詢的安全性
  • III. 系統管理
    • 16. 以預編譯套件安裝
    • 17. 以原始碼安裝
      • 17.1. 簡要步驟
      • 17.2. 環境需求
      • 17.3. Getting The Source
      • 17.4. 安裝流程
      • 17.5. Post-Installation Setup
      • 17.6. Supported Platforms
      • 17.7. 平台相關的注意事項
    • 18. 以原始碼在 Windows 上安裝
      • 18.1. Building with Visual C++ or the Microsoft Windows SDK
    • 19. 服務配置與維運
      • 19.1. PostgreSQL 使用者帳號
      • 19.2. Creating a Database Cluster
      • 19.3. Starting the Database Server
      • 19.4. 核心資源管理
      • 19.5. Shutting Down the Server
      • 19.6. Upgrading a PostgreSQL Cluster
      • 19.7. Preventing Server Spoofing
      • 19.8. Encryption Options
      • 19.9. Secure TCP/IP Connections with SSL
      • 19.10. Secure TCP/IP Connections with GSSAPI Encryption
      • 19.11. Secure TCP/IP Connections with SSH Tunnels
      • 19.12. 在 Windows 註冊事件日誌
    • 20. 服務組態設定
      • 20.1. Setting Parameters
      • 20.2. File Locations
      • 20.3. 連線與認證
      • 20.4. 資源配置
      • 20.5. Write Ahead Log
      • 20.6. 複寫(Replication)
      • 20.7. 查詢規畫
      • 20.8. 錯誤回報與日誌記錄
      • 20.9. 執行階段統計資訊
      • 20.10. 自動資料庫清理
      • 20.11. 用戶端連線預設參數
      • 20.12. 交易鎖定管理
      • 20.13. 版本與平台的相容性
      • 20.14. Error Handling
      • 20.15. 預先配置的參數
      • 20.16. Customized Options
      • 20.17. Developer Options
      • 20.18. Short Options
    • 21. 使用者認證
      • 21.1. 設定檔:pg_hba.conf
      • 21.2. User Name Maps
      • 21.3. Authentication Methods
      • 21.4. Trust Authentication
      • 21.5. Password Authentication
      • 21.6. GSSAPI Authentication
      • 21.7. SSPI Authentication
      • 21.8. Ident Authentication
      • 21.9. Peer Authentication
      • 21.10. LDAP Authentication
      • 21.11. RADIUS Authentication
      • 21.12. Certificate Authentication
      • 21.13. PAM Authentication
      • 21.14. BSD Authentication
      • 21.15. Authentication Problems
    • 22. 資料庫角色
      • 22.1. Database Roles
      • 22.2. Role Attributes
      • 22.3. Role Membership
      • 22.4. 移除角色
      • 22.5. Default Roles
      • 22.6. Function Security
    • 23. 管理資料庫
      • 23.1. Overview
      • 23.2. Creating a Database
      • 23.3. 樣版資料庫
      • 23.4. Database Configuration
      • 23.5. Destroying a Database
      • 23.6. Tablespaces
    • 24. 語系
      • 24.1. 語系支援
      • 24.2. Collation Support
      • 24.3. 字元集支援
    • 25. 例行性資料庫維護工作
      • 25.1. 例行性資料清理
      • 25.2. 定期重建索引
      • 25.3. Log 檔案維護
    • 26. 備份及還原
      • 26.1. SQL Dump
      • 26.2. 檔案系統層級備份
      • 26.3. 持續封存及 Point-in-Time Recovery (PITR)
    • 27. High Availability, Load Balancing, and Replication
      • 27.1. 比較不同的解決方案
      • 27.2. 日誌轉送備用伺服器 Log-Shipping Standby Servers
      • 27.3. Failover
      • 27.4. Hot Standby
    • 28. 監控資料庫活動
      • 28.1. 標準的 Unix 工具
      • 28.2. 統計資訊收集器
      • 28.3. Viewing Locks
      • 28.4. Progress Reporting
      • 28.5. Dynamic Tracing
    • 29. 監控磁碟使用情況
      • 29.1. 瞭解磁碟使用情形
      • 29.2. 磁碟空間不足錯誤
    • 30. 高可靠度及預寫日誌
      • 30.1. 可靠度
      • 30.2. Data Checksums
      • 30.3. Write-Ahead Logging(WAL)
      • 30.4. Asynchronous Commit
      • 30.5. WAL Configuration
      • 30.6. WAL Internals
    • 31. 邏輯複寫(Logical Replication)
      • 31.1. 發佈(Publication)
      • 31.2. 訂閱(Subscription)
      • 31.3. Row Filters
      • 31.4. Column Lists
      • 31.5. 衝突處理
      • 31.6. 限制
      • 31.7. 架構
      • 31.8. 監控
      • 31.9. 安全性
      • 31.10. 系統設定
      • 31.11. 快速設定
    • 32. Just-in-Time Compilation(JIT)
      • 32.1. What is JIT compilation?
      • 32.2. When to JIT?
      • 32.3. Configuration
      • 32.4. Extensibility
    • 33. 迴歸測試
      • 33.1. Running the Tests
      • 33.2. Test Evaluation
      • 33.3. Variant Comparison Files
      • 33.4. TAP Tests
      • 33.5. Test Coverage Examination
  • IV. 用戶端介面
    • 34. libpq - C Library
      • 33.1. 資料庫連線控制函數
      • 33.2. 連線狀態函數
      • 33.3. Command Execution Functions
      • 33.4. Asynchronous Command Processing
      • 33.5. Retrieving Query Results Row-By-Row
      • 33.6. Canceling Queries in Progress
      • 33.7. The Fast-Path Interface
      • 33.8. Asynchronous Notification
      • 33.9. Functions Associated with the COPY Command
      • 33.10. Control Functions
      • 33.11. Miscellaneous Functions
      • 33.12. Notice Processing
      • 33.13. Event System
      • 33.14. 環境變數
      • 34.16. 密碼檔
      • 33.16. The Connection Service File
      • 33.17. LDAP Lookup of Connection Parameters
      • 33.18. SSL Support
      • 33.19. Behavior in Threaded Programs
      • 33.20. Building libpq Programs
      • 33.21. Example Programs
    • 35. Large Objects
      • 35.1. Introduction
      • 35.2. Implementation Features
      • 35.3. Client Interfaces
      • 35.4. Server-side Functions
      • 35.5. Example Program
    • 36. ECPG - Embedded SQL in C
      • 35.1. The Concept
      • 35.2. Managing Database Connections
      • 35.3. Running SQL Commands
      • 35.4. Using Host Variables
      • 35.5. Dynamic SQL
      • 35.6. pgtypes Library
      • 35.7. Using Descriptor Areas
      • 35.8. Error Handling
      • 35.9. Preprocessor Directives
      • 35.10. Processing Embedded SQL Programs
      • 35.11. Library Functions
      • 35.12. Large Objects
      • 35.13. C++ Applications
      • 35.14. Embedded SQL Commands
      • 35.15. Informix Compatibility Mode
      • 35.16. Internals
    • 37. The Information Schema
      • 37.1. The Schema
      • 37.2. Data Types
      • 37.3. information_schema_catalog_name
      • 37.4. administrable_role_authorizations
      • 37.5. applicable_roles
      • 37.7. attributes
      • 37.7. character_sets
      • 37.8. check_constraint_routine_usage
      • 37.9. check_constraints
      • 37.10. collations
      • 37.11. collation_character_set_applicability
      • 37.12. column_column_usage
      • 37.13. column_domain_usage
      • 37.14. column_options
      • 37.15. column_privileges
      • 37.16. column_udt_usage
      • 37.17. columns
      • 37.18. constraint_column_usage
      • 37.19. constraint_table_usage
      • 37.20. data_type_privileges
      • 37.21. domain_constraints
      • 37.21. domain_udt_usage
      • 37.22. domains
      • 37.23. element_types
      • 37.24. enabled_roles
      • 37.25. foreign_data_wrapper_options
      • 37.26. foreign_data_wrappers
      • 37.27. foreign_server_options
      • 37.28. foreign_servers
      • 37.29. foreign_table_options
      • 37.30. foreign_tables
      • 36.32. key_column_usage
      • 37.33. parameters
      • 36.34. referential_constraints
      • 37.34. role_column_grants
      • 37.35. role_routine_grants
      • 37.37. role_table_grants
      • 37.38. role_udt_grants
      • 37.39. role_usage_grants
      • 37.40. routine_column_usage
      • 37.41. routine_privileges
      • 37.45. routines
      • 37.46. schemata
      • 37.47. sequences
      • 37.48. sql_features
      • 37.49. sql_implementation_info
      • 37.50. sql_parts
      • 37.51. sql_sizing
      • 36.51. table_constraints
      • 36.49. table_privileges
      • 37.52. tables
      • 37.53. transforms
      • 37.54. triggered_update_columns
      • 37.55. triggers
      • 37.56. udt_privileges
      • 37.57. usage_privileges
      • 37.58. user_defined_types
      • 37.59. user_mapping_options
      • 37.60. user_mappings
      • 37.63. view_column_usage
      • 37.64. view_routine_usage
      • 37.65. view_table_usage
      • 37.66. views
  • V. 資料庫程式設計
    • 38. SQL 延伸功能
      • 38.1. How Extensibility Works
      • 38.2. The PostgreSQL Type System
      • 38.3. 使用者自訂函數
      • 38.4. User-defined Procedures
      • 38.5. Query Language (SQL) Functions
      • 38.6. Function Overloading
      • 38.7. 函數易變性類別
      • 38.8. Procedural Language Functions
      • 38.9. Internal Functions
      • 38.10. C-Language Functions
      • 38.11. Function Optimization Information
      • 38.12. User-defined Aggregates
      • 38.13. User-defined Types
      • 38.14. User-defined Operators
      • 38.15. Operator Optimization Information
      • 38.16. Interfacing Extensions To Indexes
      • 38.17. 封裝相關物件到延伸功能中
      • 38.18. Extension Building Infrastructure
    • 39. Triggers
      • 39.1. Overview of Trigger Behavior
      • 39.2. Visibility of Data Changes
      • 39.3. Writing Trigger Functions in C
      • 39.4. A Complete Trigger Example
    • 40. Event Triggers (事件觸發)
      • 40.1. Overview of Event Trigger Behavior
      • 40.2. Event Trigger Firing Matrix
      • 40.3. Writing Event Trigger Functions in C
      • 40.4. A Complete Event Trigger Example
    • 41. 規則系統
      • 41.1. The Query Tree
      • 41.2. Views and the Rule System
      • 41.3. Materialized Views
      • 41.4. Rules on INSERT, UPDATE, and DELETE
      • 41.5. 規則及權限
      • 41.6. Rules and Command Status
      • 41.7. Rules Versus Triggers
    • 42. Procedural Languages(程序語言)
      • 42.1. Installing Procedural Languages
    • 43. PL/pgSQL - SQL Procedural Language
      • 43.1. Overview
      • 43.2. Structure of PL/pgSQL
      • 43.3. Declarations
      • 43.4. Expressions
      • 43.5. 基本語法
      • 43.6. Control Structures
      • 43.7. Cursors
      • 43.8. Transaction Management
      • 43.9. Errors and Messages
      • 43.10. Trigger Functions
      • 43.11. PL/pgSQL under the Hood
      • 43.12. Tips for Developing in PL/pgSQL
      • 43.13. Porting from Oracle PL/SQL
    • 44. PL/Tcl - Tcl Procedural Language
    • 45. PL/Perl — Perl Procedural Language
    • 46. PL/Python - Python Procedural Language
      • 46.1. PL/Python Functions
      • 46.2. Data Values
      • 46.3. Sharing Data
      • 46.4. Anonymous Code Blocks
      • 46.5. Trigger Functions
      • 46.6. Database Access
      • 46.7. Explicit Subtransactions
      • 46.8. Transaction Management
      • 46.9. Utility Functions
      • 46.10. Python 2 vs. Python 3
      • 46.11. Environment Variables
    • 47. Server Programming Interface
    • 48. Background Worker Processes
    • 49. Logical Decoding
      • 48.1. Logical Decoding Examples
      • 48.2. Logical Decoding Concepts
      • 48.3. Streaming Replication Protocol Interface
      • 48.4. Logical Decoding SQL Interface
      • 48.5. System Catalogs Related to Logical Decoding
      • 48.6. Logical Decoding Output Plugins
      • 48.7. Logical Decoding Output Writers
      • 48.8. Synchronous Replication Support for Logical Decoding
    • 50. Replication Progress Tracking
    • 51. Archive Modules
      • 51.1. Initialization Functions
      • 51.2. Archive Module Callbacks
  • VI. 參考資訊
    • I. SQL 指令
      • ALTER DATABASE
      • ALTER DEFAULT PRIVILEGES
      • ALTER EXTENSION
      • ALTER FUNCTION
      • ALTER INDEX
      • ALTER LANGUAGE
      • ALTER MATERIALIZED VIEW
      • ALTER POLICY
      • ALTER PUBLICATION
      • ALTER ROLE
      • ALTER RULE
      • ALTER SCHEMA
      • ALTER SEQUENCE
      • ALTER STATISTICS
      • ALTER SUBSCRIPTION
      • ALTER SYSTEM
      • ALTER TABLE
      • ALTER TABLESPACE
      • ALTER TRIGGER
      • ALTER TYPE
      • ALTER USER
      • ALTER VIEW
      • ANALYZE
      • CLUSTER
      • COMMENT
      • COMMIT PREPARED
      • COPY
      • CREATE ACCESS METHOD
      • CREATE CAST
      • CREATE DATABASE
      • CREATE EVENT TRIGGER
      • CREATE EXTENSION
      • CREATE FOREIGN TABLE
      • CREATE FOREIGN DATA WRAPPER
      • CREATE FUNCTION
      • CREATE INDEX
      • CREATE LANGUAGE
      • CREATE MATERIALIZED VIEW
      • CREATE DOMAIN
      • CREATE POLICY
      • CREATE PROCEDURE
      • CREATE PUBLICATION
      • CREATE ROLE
      • CREATE RULE
      • CREATE SCHEMA
      • CREATE SEQUENCE
      • CREATE SERVER
      • CREATE STATISTICS
      • CREATE SUBSCRIPTION
      • CREATE TABLE
      • CREATE TABLE AS
      • CREATE TABLESPACE
      • CREATE TRANSFORM
      • CREATE TRIGGER
      • CREATE TYPE
      • CREATE USER
      • CREATE USER MAPPING
      • CREATE VIEW
      • DEALLOCATE
      • DELETE
      • DO
      • DROP ACCESS METHOD
      • DROP DATABASE
      • DROP EXTENSION
      • DROP FUNCTION
      • DROP INDEX
      • DROP LANGUAGE
      • DROP MATERIALIZED VIEW
      • DROP OWNED
      • DROP POLICY
      • DROP PUBLICATION
      • DROP ROLE
      • DROP RULE
      • DROP SCHEMA
      • DROP SEQUENCE
      • DROP STATISTICS
      • DROP SUBSCRIPTION
      • DROP TABLE
      • DROP TABLESPACE
      • DROP TRANSFORM
      • DROP TRIGGER
      • DROP TYPE
      • DROP USER
      • DROP VIEW
      • EXECUTE
      • EXPLAIN
      • GRANT
      • IMPORT FOREIGN SCHEMA
      • INSERT
      • LISTEN
      • LOAD
      • MERGE
      • NOTIFY
      • PREPARE
      • PREPARE TRANSACTION
      • REASSIGN OWNED
      • REFRESH MATERIALIZED VIEW
      • REINDEX
      • RESET
      • REVOKE
      • ROLLBACK PREPARED
      • SECURITY LABEL
      • SELECT
      • SELECT INTO
      • SET
      • SET CONSTRAINTS
      • SET ROLE
      • SET SESSION AUTHORIZATION
      • SET TRANSACTION
      • SHOW
      • TRUNCATE
      • UNLISTEN
      • UPDATE
      • VACUUM
      • VALUES
    • II. PostgreSQL 用戶端工具
      • createdb
      • createuser
      • dropdb
      • dropuser
      • oid2name
      • pgbench
      • pg_basebackup
      • pg_dump
      • pg_dumpall
      • pg_isready
      • pg_receivewal
      • pg_recvlogical
      • pg_restore
      • pg_verifybackup
      • psql
      • vacuumdb
    • III. PostgreSQL 伺服器應用程式
      • initdb
      • pg_archivecleanup
      • pg_ctl
      • pg_standby
      • pg_test_fsync
      • pg_test_timing
      • pg_upgrade
      • postgres
  • VII. 資料庫進階
    • 52. PostgreSQL 的內部架構
      • 52.1. 處理查詢語句的流程
      • 52.2. How Connections Are Established
      • 52.3. The Parser Stage
      • 52.4. The PostgreSQL Rule System
      • 52.5. Planner/Optimizer
      • 52.6. Executor
    • 53. 系統資訊目錄
      • 51.3. pg_am
      • 51.7. pg_attribute
      • 51.8. pg_authid
      • 51.9. pg_auth_members
      • 51.10. pg_cast
      • 51.11 pg_class
      • 51.12. pg_collation
      • 51.13. pg_constraint
      • 51.15 pg_database
      • 51.21. pg_event_trigger
      • 51.22. pg_extension
      • 51.26 pg_index
      • 51.29. pg_language
      • 51.32. pg_namespace
      • 51.33. pg_opclass
      • 51.38. pg_policy
      • 51.39. pg_proc
      • 51.44. pg_rewrite
      • 51.49. pg_statistic
      • 51.50. pg_statistic_ext
      • 51.52. pg_subscription
      • 51.53. pg_subscription_rel
      • 51.54. pg_tablespace
      • 51.56. pg_trigger
      • 51.62. pg_type
      • 51.66. pg_available_extensions
      • 51.67. pg_available_extension_versions
      • 51.71. pg_hba_file_rules
      • 51.72. pg_indexes
      • 51.73. pg_locks
      • 51.77. pg_prepared_xacts
      • 51.79. pg_replication_origin_status
    • 54. System Views
      • 54.1. Overview
      • 54.19. pg_replication_slots
      • 54.20 pg_roles
      • 54.24. pg_settings
      • 54.25. pg_shadow
      • 54.26. pg_shmem_allocations
      • 54.27. pg_stats
      • 54.30. pg_tables
      • 54.31. pg_timezone_abbrevs
      • 54.32. pg_timezone_names
      • 54.33. pg_user
      • 54.35. pg_views
    • 55. Frontend/Backend Protocol
      • 52.1. Overview
      • 52.2. Message Flow
      • 52.3. SASL Authentication
      • 52.4. Streaming Replication Protocol
      • 52.5. Logical Streaming Replication Protocol
      • 52.6. Message Data Types
      • 52.7. Message Formats
      • 52.8. Error and Notice Message Fields
      • 52.9. Logical Replication Message Formats
      • 52.10. Summary of Changes since Protocol 2.0
    • 56. PostgreSQL 程式撰寫慣例
      • 53.1. Formatting
      • 53.2. Reporting Errors Within the Server
      • 53.3. Error Message Style Guide
      • 53.4. Miscellaneous Coding Conventions
    • 57. Native Language Support
      • 54.1. For the Translator
      • 54.2. For the Programmer
    • 58. 撰寫程序語言的處理程序
    • 59. Writing a Foreign Data Wrapper
      • 56.1. Foreign Data Wrapper Functions
      • 56.2. Foreign Data Wrapper Callback Routines
      • 56.3. Foreign Data Wrapper Helper Functions
      • 56.4. Foreign Data Wrapper Query Planning
      • 56.5. Row Locking in Foreign Data Wrappers
    • 60. Writing a Table Sampling Method
    • 61. Writing a Custom Scan Provider
    • 62. Genetic Query Optimizer
      • 59.1. Query Handling as a Complex Optimization Problem
      • 59.2. Genetic Algorithms
      • 59.3. Genetic Query Optimization (GEQO) in PostgreSQL
      • 59.4. Further Reading
    • 63. Table Access Method Interface Definition
    • 64. Index Access Method Interface Definition
    • 65. Generic WAL Records
    • 66. Custom WAL Resource Managers
    • 67. B-Tree Indexes
      • 67.1. Introduction
      • 67.2. Behavior of B-Tree Operator Classes
      • 67.3. B-Tree Support Functions
      • 67.4. Implementation
    • 68. GiST Indexes
      • 64.1. Introduction
      • 64.2. Built-in Operator Classes
      • 64.3. Extensibility
      • 64.4. Implementation
      • 64.5. Examples
    • 69. SP-GiST Indexes
      • 65.1. Introduction
      • 65.2. Built-in Operator Classes
      • 65.3. Extensibility
      • 65.4. Implementation
      • 65.5. Examples
    • 70. GIN 索引
      • 70.1. 簡介
      • 70.2. 內建運算子類
      • 70.3. 延伸介面
      • 70.4. 實作說明
      • 70.5. GIN 小技巧
      • 70.6. 限制
      • 70.7. 範例
    • 71. BRIN Indexes
      • 67.1. Introduction
      • 67.2. Built-in Operator Classes
      • 67.3. Extensibility
    • 72. Hash Indexes
    • 73. 資料庫實體儲存格式
      • 73.1. Database File Layout
      • 73.3. TOAST
      • 68.3. Free Space Map
      • 68.4 可視性映射表(Visibility Map)
      • 68.5. The Initialization Fork
      • 68.6. Database Page Layout
    • 74. System Catalog Declarations and Initial Contents
    • 75. 查詢計畫如何使用統計資訊
      • 70.1. Row Estimation Examples
      • 70.2. 多元統計資訊範例
      • 70.3. Planner Statistics and Security
    • 76. Backup Manifest Format
  • VIII. 附錄
    • A. PostgreSQL 錯誤代碼
    • B. 日期時間格式支援
      • B.1. 日期時間解譯流程
      • B.2. Handling of Invalid or Ambiguous Timestamps
      • B.3. 日期時間慣用字
      • B.4. 日期時間設定檔
      • B.5. POSIX Time Zone Specifications
      • B.6. 日期時間的沿革
      • B.7. Julian Dates
    • C. SQL 關鍵字
    • D. SQL 相容性
      • D.1. Supported Features
      • D.2. Unsupported Features
      • D.3. XML Limits and Conformance to SQL/XML
    • E. 版本資訊
      • E.1. Release 15.2
      • E.2. Release 15.1
      • E.3. Release 15
      • E.4. Prior Releases
    • F. 延伸支援模組
      • F.1. adminpack
      • F.2. amcheck
      • F.3. auth_delay
      • F.4. auto_explain
      • F.5. bloom
      • F.6. btree_gin
      • F.10. dblink
        • dblink_connect
        • dblink_connect_u
        • dblink_disconnect
        • dblink
        • dblink_exec
        • dblink_open
        • dblink_fetch
        • dblink_close
        • dblink_get_connections
        • dblink_error_message
        • dblink_send_query
        • dblink_is_busy
        • dblink_get_notify
        • dblink_get_result
        • dblink_cancel_query
        • dblink_get_pkey
        • dblink_build_sql_insert
        • dblink_build_sql_delete
        • dblink_build_sql_update
      • F.13. earthdistance
      • F.14. file_fdw
      • F.16. hstore
      • F.24. pg_buffercache
      • F.26. passwordcheck
      • F.29. pg_stat_statements
      • F.30. pgstattuple
      • F.31. pg_trgm
      • F.32. pg_visibility
      • F.38. postgres_fdw
      • F.35. sepgsql
      • F.43. tablefunc
      • F.45. test_decoding
      • F.46. tsm_system_rows
      • F.47. tsm_system_time
      • F.49. uuid-ossp
    • G. Additional Supplied Programs
      • G.1. Client Applications
        • oid2name
        • vacuumlo
      • G.2. Server Applications
        • pg_standby
    • H. 外部專案
      • H.1. 用戶端介面
      • H.2. Administration Tools
      • H.3. Procedural Languages
      • H.4. Extensions
    • I. The Source Code Repository
      • I.1. Getting The Source via Git
    • J. 文件取得
      • J.1. DocBook
      • J.2. Tool Sets
      • J.3. Building the Documentation
      • J.4. Documentation Authoring
      • J.5. Style Guide
    • K. PostgreSQL Limits
    • L. 縮寫字
    • M. Glossary
    • N. 色彩支援
      • N.1. When Color is Used
      • N.2. Configuring the Colors
    • O. Obsolete or Renamed Features
  • 參考書目
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  • 38.2.1. Base Types
  • 38.2.2. Container Types
  • 38.2.3. Domains
  • 38.2.4. Pseudo-Types
  • 38.2.5. Polymorphic Types

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  1. V. 資料庫程式設計
  2. 38. SQL 延伸功能

38.2. The PostgreSQL Type System

Previous38.1. How Extensibility WorksNext38.3. 使用者自訂函數

Last updated 2 years ago

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PostgreSQL data types can be divided into base types, container types, domains, and pseudo-types.

38.2.1. Base Types

Base types are those, like integer, that are implemented below the level of the SQL language (typically in a low-level language such as C). They generally correspond to what are often known as abstract data types. PostgreSQL can only operate on such types through functions provided by the user and only understands the behavior of such types to the extent that the user describes them. The built-in base types are described in .

Enumerated (enum) types can be considered as a subcategory of base types. The main difference is that they can be created using just SQL commands, without any low-level programming. Refer to for more information.

38.2.2. Container Types

PostgreSQL has three kinds of “container” types, which are types that contain multiple values of other types. These are arrays, composites, and ranges.

Arrays can hold multiple values that are all of the same type. An array type is automatically created for each base type, composite type, range type, and domain type. But there are no arrays of arrays. So far as the type system is concerned, multi-dimensional arrays are the same as one-dimensional arrays. Refer to for more information.

Composite types, or row types, are created whenever the user creates a table. It is also possible to use to define a “stand-alone” composite type with no associated table. A composite type is simply a list of types with associated field names. A value of a composite type is a row or record of field values. Refer to for more information.

A range type can hold two values of the same type, which are the lower and upper bounds of the range. Range types are user-created, although a few built-in ones exist. Refer to for more information.

38.2.3. Domains

A domain is based on a particular underlying type and for many purposes is interchangeable with its underlying type. However, a domain can have constraints that restrict its valid values to a subset of what the underlying type would allow. Domains are created using the SQL command . Refer to for more information.

38.2.4. Pseudo-Types

There are a few “pseudo-types” for special purposes. Pseudo-types cannot appear as columns of tables or components of container types, but they can be used to declare the argument and result types of functions. This provides a mechanism within the type system to identify special classes of functions. lists the existing pseudo-types.

38.2.5. Polymorphic Types

Table 38.1. Polymorphic Types

Name
Family
Description

anyelement

Simple

Indicates that a function accepts any data type

anyarray

Simple

Indicates that a function accepts any array data type

anynonarray

Simple

Indicates that a function accepts any non-array data type

anyenum

Simple

anyrange

Simple

anymultirange

Simple

anycompatible

Common

Indicates that a function accepts any data type, with automatic promotion of multiple arguments to a common data type

anycompatiblearray

Common

Indicates that a function accepts any array data type, with automatic promotion of multiple arguments to a common data type

anycompatiblenonarray

Common

Indicates that a function accepts any non-array data type, with automatic promotion of multiple arguments to a common data type

anycompatiblerange

Common

Indicates that a function accepts any range data type, with automatic promotion of multiple arguments to a common data type

anycompatiblemultirange

Common

Indicates that a function accepts any multirange data type, with automatic promotion of multiple arguments to a common data type

Polymorphic arguments and results are tied to each other and are resolved to specific data types when a query calling a polymorphic function is parsed. When there is more than one polymorphic argument, the actual data types of the input values must match up as described below. If the function's result type is polymorphic, or it has output parameters of polymorphic types, the types of those results are deduced from the actual types of the polymorphic inputs as described below.

For the “simple” family of polymorphic types, the matching and deduction rules work like this:

Each position (either argument or return value) declared as anyelement is allowed to have any specific actual data type, but in any given call they must all be the same actual type. Each position declared as anyarray can have any array data type, but similarly they must all be the same type. And similarly, positions declared as anyrange must all be the same range type. Likewise for anymultirange.

Furthermore, if there are positions declared anyarray and others declared anyelement, the actual array type in the anyarray positions must be an array whose elements are the same type appearing in the anyelement positions. anynonarray is treated exactly the same as anyelement, but adds the additional constraint that the actual type must not be an array type. anyenum is treated exactly the same as anyelement, but adds the additional constraint that the actual type must be an enum type.

Similarly, if there are positions declared anyrange and others declared anyelement or anyarray, the actual range type in the anyrange positions must be a range whose subtype is the same type appearing in the anyelement positions and the same as the element type of the anyarray positions. If there are positions declared anymultirange, their actual multirange type must contain ranges matching parameters declared anyrange and base elements matching parameters declared anyelement and anyarray.

Thus, when more than one argument position is declared with a polymorphic type, the net effect is that only certain combinations of actual argument types are allowed. For example, a function declared as equal(anyelement, anyelement) will take any two input values, so long as they are of the same data type.

When the return value of a function is declared as a polymorphic type, there must be at least one argument position that is also polymorphic, and the actual data type(s) supplied for the polymorphic arguments determine the actual result type for that call. For example, if there were not already an array subscripting mechanism, one could define a function that implements subscripting as subscript(anyarray, integer) returns anyelement. This declaration constrains the actual first argument to be an array type, and allows the parser to infer the correct result type from the actual first argument's type. Another example is that a function declared as f(anyarray) returns anyenum will only accept arrays of enum types.

In most cases, the parser can infer the actual data type for a polymorphic result type from arguments that are of a different polymorphic type in the same family; for example anyarray can be deduced from anyelement or vice versa. An exception is that a polymorphic result of type anyrange requires an argument of type anyrange; it cannot be deduced from anyarray or anyelement arguments. This is because there could be multiple range types with the same subtype.

Note that anynonarray and anyenum do not represent separate type variables; they are the same type as anyelement, just with an additional constraint. For example, declaring a function as f(anyelement, anyenum) is equivalent to declaring it as f(anyenum, anyenum): both actual arguments have to be the same enum type.

Since there is no way to select a range type knowing only its subtype, use of anycompatiblerange and/or anycompatiblemultirange requires that all arguments declared with that type have the same actual range and/or multirange type, and that that type's subtype agree with the selected common type, so that no casting of the range values is required. As with anyrange and anymultirange, use of anycompatiblerange and anymultirange as a function result type requires that there be an anycompatiblerange or anycompatiblemultirange argument.

Notice that there is no anycompatibleenum type. Such a type would not be very useful, since there normally are not any implicit casts to enum types, meaning that there would be no way to resolve a common type for dissimilar enum inputs.

The “simple” and “common” polymorphic families represent two independent sets of type variables. Consider for example

CREATE FUNCTION myfunc(a anyelement, b anyelement,
                       c anycompatible, d anycompatible)
RETURNS anycompatible AS ...

In an actual call of this function, the first two inputs must have exactly the same type. The last two inputs must be promotable to a common type, but this type need not have anything to do with the type of the first two inputs. The result will have the common type of the last two inputs.

Some pseudo-types of special interest are the polymorphic types, which are used to declare polymorphic functions. This powerful feature allows a single function definition to operate on many different data types, with the specific data type(s) being determined by the data types actually passed to it in a particular call. The polymorphic types are shown in . Some examples of their use appear in .

Indicates that a function accepts any enum data type (see )

Indicates that a function accepts any range data type (see )

Indicates that a function accepts any multirange data type (see )

For the “common” family of polymorphic types, the matching and deduction rules work approximately the same as for the “simple” family, with one major difference: the actual types of the arguments need not be identical, so long as they can be implicitly cast to a single common type. The common type is selected following the same rules as for UNION and related constructs (see ). Selection of the common type considers the actual types of anycompatible and anycompatiblenonarray inputs, the array element types of anycompatiblearray inputs, the range subtypes of anycompatiblerange inputs, and the multirange subtypes of anycompatiblemultirange inputs. If anycompatiblenonarray is present then the common type is required to be a non-array type. Once a common type is identified, arguments in anycompatible and anycompatiblenonarray positions are automatically cast to that type, and arguments in anycompatiblearray positions are automatically cast to the array type for that type.

A variadic function (one taking a variable number of arguments, as in ) can be polymorphic: this is accomplished by declaring its last parameter as VARIADIC anyarray or VARIADIC anycompatiblearray. For purposes of argument matching and determining the actual result type, such a function behaves the same as if you had written the appropriate number of anynonarray or anycompatiblenonarray parameters.

Chapter 8
Section 8.7
Section 8.15
CREATE TYPE
Section 8.16
Section 8.17
CREATE DOMAIN
Section 8.18
Table 8.27
Table 38.1
Section 38.5.11
Section 10.5
Section 38.5.6
Section 8.7
Section 8.17
Section 8.17