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前言 何為PostgreSQL? PostgreSQL簡史 格式約定 更多信息 臭蟲匯報指導(dǎo) I. 教程 章1. 從頭開始 1.1. 安裝 1.2. 體系基本概念 1.3. 創(chuàng)建一個數(shù)據(jù)庫 1.4. 訪問數(shù)據(jù)庫 章2. SQL語言 2.1. 介紹 2.2. 概念 2.3. 創(chuàng)建新表 2.4. 向表中添加行 2.5. 查詢一個表 2.6. 表間鏈接 2.7. 聚集函數(shù) 2.8. 更新 2.9. 刪除 章3. 高級特性 3.1. 介紹 3.2. 視圖 3.3. 外鍵 3.4. 事務(wù) 3.5. 窗口函數(shù) 3.6. 繼承 3.7. 結(jié)論 II. SQL語言 章4. SQL語法 4.1. 詞法結(jié)構(gòu) 4.2. 值表達(dá)式 4.3. 調(diào)用函數(shù) 章5. 數(shù)據(jù)定義 5.1. 表的基本概念 5.2. 缺省值 5.3. 約束 5.4. 系統(tǒng)字段 5.5. 修改表 5.6. 權(quán)限 5.7. 模式 5.8. 繼承 5.9. 分區(qū) 5.10. 其它數(shù)據(jù)庫對象 5.11. 依賴性跟蹤 章 6. 數(shù)據(jù)操作 6.1. 插入數(shù)據(jù) 6.2. 更新數(shù)據(jù) 6.3. 刪除數(shù)據(jù) 章7. 查詢 7.1. 概述 7.2. 表表達(dá)式 7.3. 選擇列表 7.4. 組合查詢 7.5. 行排序 7.6. LIMIT和OFFSET 7.7. VALUES列表 7.8. WITH的查詢(公用表表達(dá)式) 章8. 數(shù)據(jù)類型 8.1. 數(shù)值類型 8.2. 貨幣類型 8.3. 字符類型 8.4. 二進(jìn)制數(shù)據(jù)類型 8.5. 日期/時間類型 8.6. 布爾類型 8.7. 枚舉類型 8.8. 幾何類型 8.9. 網(wǎng)絡(luò)地址類型 8.10. 位串類型 8.11. 文本搜索類型 8.12. UUID類型 8.13. XML類型 8.14. 數(shù)組 8.15. 復(fù)合類型 8.16. 對象標(biāo)識符類型 8.17. 偽類型 章 9. 函數(shù)和操作符 9.1. 邏輯操作符 9.2. 比較操作符 9.3. 數(shù)學(xué)函數(shù)和操作符 9.4. 字符串函數(shù)和操作符 9.5. 二進(jìn)制字符串函數(shù)和操作符 9.6. 位串函數(shù)和操作符 9.7. 模式匹配 9.8. 數(shù)據(jù)類型格式化函數(shù) 9.9. 時間/日期函數(shù)和操作符 9.10. 支持枚舉函數(shù) 9.11. 幾何函數(shù)和操作符 9.12. 網(wǎng)絡(luò)地址函數(shù)和操作符 9.13. 文本檢索函數(shù)和操作符 9.14. XML函數(shù) 9.15. 序列操作函數(shù) 9.16. 條件表達(dá)式 9.17. 數(shù)組函數(shù)和操作符 9.18. 聚合函數(shù) 9.19. 窗口函數(shù) 9.20. 子查詢表達(dá)式 9.21. 行和數(shù)組比較 9.22. 返回集合的函數(shù) 9.23. 系統(tǒng)信息函數(shù) 9.24. 系統(tǒng)管理函數(shù) 9.25. 觸發(fā)器函數(shù) 章10. 類型轉(zhuǎn)換 10.3. 函數(shù) 10.2. 操作符 10.1. 概述 10.4. 值存儲 10.5. UNION 章11. 索引 11.1. 介紹 11.2. 索引類型 11.3. 多字段索引 11.4. 索引和ORDER BY 11.5. 組合多個索引 11.6. 唯一索引 11.7. 表達(dá)式上的索引 11.8. 部分索引 11.9. 操作類和操作簇 11.10. 檢查索引的使用 章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. GiST and GIN Index Types 12.10. psql Support 12.11. Limitations 12.12. Migration from Pre-8.3 Text Search 章13. 并發(fā)控制 13.1. 介紹 13.2. 事務(wù)隔離 13.3. 明確鎖定 13.4. 應(yīng)用層數(shù)據(jù)完整性檢查 13.5. 鎖和索引 章14. 性能提升技巧 14.1. 使用EXPLAIN 14.2. 規(guī)劃器使用的統(tǒng)計信息 14.3. 用明確的JOIN語句控制規(guī)劃器 14.4. 向數(shù)據(jù)庫中添加記錄 14.5. 非持久性設(shè)置 III. 服務(wù)器管理 章15. 安裝指導(dǎo) 15.1. 簡版 15.2. 要求 15.3. 獲取源碼 15.4. 升級 15.5. 安裝過程 15.6. 安裝后的設(shè)置 15.7. 支持的平臺 15.8. 特殊平臺的要求 章16. Installation from Source Code on Windows 16.1. Building with Visual C++ or the Platform SDK 16.2. Building libpq with Visual C++ or Borland C++ 章17. 服務(wù)器安裝和操作 17.1. PostgreSQL用戶帳戶 17.2. 創(chuàng)建數(shù)據(jù)庫集群 17.3. 啟動數(shù)據(jù)庫服務(wù)器 17.4. 管理內(nèi)核資源 17.5. 關(guān)閉服務(wù) 17.6. 防止服務(wù)器欺騙 17.7. 加密選項 17.8. 用SSL進(jìn)行安全的TCP/IP連接 17.9. Secure TCP/IP Connections with SSH Tunnels 章18. 服務(wù)器配置 18.1. 設(shè)置參數(shù) 18.2. 文件位置 18.3. 連接和認(rèn)證 18.4. 資源消耗 18.5. 預(yù)寫式日志 18.6. 查詢規(guī)劃 18.7. 錯誤報告和日志 18.8. 運(yùn)行時統(tǒng)計 18.9. 自動清理 18.10. 客戶端連接缺省 18.12. 版本和平臺兼容性 18.11. 鎖管理 18.13. 預(yù)置選項 18.14. 自定義的選項 18.15. 開發(fā)人員選項 18.16. 短選項 章19. 用戶認(rèn)證 19.1. pg_hba.conf 文件 19.2. 用戶名映射 19.3. 認(rèn)證方法 19.4. 用戶認(rèn)證 章20. 數(shù)據(jù)庫角色和權(quán)限 20.1. 數(shù)據(jù)庫角色 20.2. 角色屬性 20.3. 權(quán)限 20.4. 角色成員 20.5. 函數(shù)和觸發(fā)器 章21. 管理數(shù)據(jù)庫 21.1. 概述 21.2. 創(chuàng)建一個數(shù)據(jù)庫 21.3. 臨時庫 21.4. 數(shù)據(jù)庫配置 21.5. 刪除數(shù)據(jù)庫 21.6. 表空間 章22. 本土化 22.1. 區(qū)域支持 22.2. 字符集支持 章23. 日常數(shù)據(jù)庫維護(hù)工作 23.1. Routine Vacuuming日常清理 23.2. 經(jīng)常重建索引 23.3. 日志文件維護(hù) 章24. 備份和恢復(fù) 24.1. SQL轉(zhuǎn)儲 24.2. 文件系統(tǒng)級別的備份 24.3. 在線備份以及即時恢復(fù)(PITR) 24.4. 版本間遷移 章25. 高可用性與負(fù)載均衡,復(fù)制 25.1. 不同解決方案的比較 25.2. 日志傳送備份服務(wù)器 25.3. 失效切換 25.4. 日志傳送的替代方法 25.5. 熱備 章26. 恢復(fù)配置 26.1. 歸檔恢復(fù)設(shè)置 26.2. 恢復(fù)目標(biāo)設(shè)置 26.3. 備服務(wù)器設(shè)置 章27. 監(jiān)控數(shù)據(jù)庫的活動 27.1. 標(biāo)準(zhǔn)Unix工具 27.2. 統(tǒng)計收集器 27.3. 查看鎖 27.4. 動態(tài)跟蹤 章28. 監(jiān)控磁盤使用情況 28.1. 判斷磁盤的使用量 28.2. 磁盤滿導(dǎo)致的失效 章29. 可靠性和預(yù)寫式日志 29.1. 可靠性 29.2. 預(yù)寫式日志(WAL) 29.3. 異步提交 29.4. WAL配置 29.5. WAL內(nèi)部 章30. Regression Tests 30.1. Running the Tests 30.2. Test Evaluation 30.3. Variant Comparison Files 30.4. Test Coverage Examination IV. 客戶端接口 章31. libpq-C庫 31.1. 數(shù)據(jù)庫聯(lián)接函數(shù) 31.2. 連接狀態(tài)函數(shù) 31.3. 命令執(zhí)行函數(shù) 31.4. 異步命令處理 31.5. 取消正在處理的查詢 31.6. 捷徑接口 31.7. 異步通知 31.8. 與COPY命令相關(guān)的函數(shù) 31.9. Control Functions 控制函數(shù) 31.10. 其他函數(shù) 31.11. 注意信息處理 31.12. 事件系統(tǒng) 31.13. 環(huán)境變量 31.14. 口令文件 31.15. 連接服務(wù)的文件 31.16. LDAP查找連接參數(shù) 31.17. SSL支持 31.18. 在多線程程序里的行為 31.19. 制作libpq程序 31.20. 例子程序 章32. 大對象 32.1. 介紹 32.2. 實(shí)現(xiàn)特點(diǎn) 32.3. 客戶端接口 32.4. 服務(wù)器端函數(shù) 32.5. 例子程序 章33. ECPG - Embedded SQL in C 33.1. The Concept 33.2. Connecting to the Database Server 33.3. Closing a Connection 33.4. Running SQL Commands 33.5. Choosing a Connection 33.6. Using Host Variables 33.7. Dynamic SQL 33.8. pgtypes library 33.9. Using Descriptor Areas 33.10. Informix compatibility mode 33.11. Error Handling 33.12. Preprocessor directives 33.13. Processing Embedded SQL Programs 33.14. Library Functions 33.15. Internals 章34. 信息模式 34.1. 關(guān)于這個模式 34.2. 數(shù)據(jù)類型 34.3. information_schema_catalog_name 34.4. administrable_role_authorizations 34.5. applicable_roles 34.6. attributes 34.7. check_constraint_routine_usage 34.8. check_constraints 34.9. column_domain_usage 34.10. column_privileges 34.11. column_udt_usage 34.12. 字段 34.13. constraint_column_usage 34.14. constraint_table_usage 34.15. data_type_privileges 34.16. domain_constraints 34.18. domains 34.17. domain_udt_usage 34.19. element_types 34.20. enabled_roles 34.21. foreign_data_wrapper_options 34.22. foreign_data_wrappers 34.23. foreign_server_options 34.24. foreign_servers 34.25. key_column_usage 34.26. parameters 34.27. referential_constraints 34.28. role_column_grants 34.29. role_routine_grants 34.30. role_table_grants 34.31. role_usage_grants 34.32. routine_privileges 34.33. routines 34.34. schemata 34.35. sequences 34.36. sql_features 34.37. sql_implementation_info 34.38. sql_languages 34.39. sql_packages 34.40. sql_parts 34.41. sql_sizing 34.42. sql_sizing_profiles 34.43. table_constraints 34.44. table_privileges 34.45. tables 34.46. triggered_update_columns 34.47. 觸發(fā)器 34.48. usage_privileges 34.49. user_mapping_options 34.50. user_mappings 34.51. view_column_usage 34.52. view_routine_usage 34.53. view_table_usage 34.54. 視圖 V. 服務(wù)器端編程 章35. 擴(kuò)展SQL 35.1. 擴(kuò)展性是如何實(shí)現(xiàn)的 35.2. PostgreSQL類型系統(tǒng) 35.3. User-Defined Functions 35.4. Query Language (SQL) Functions 35.5. Function Overloading 35.6. Function Volatility Categories 35.7. Procedural Language Functions 35.8. Internal Functions 35.9. C-Language Functions 35.10. User-Defined Aggregates 35.11. User-Defined Types 35.12. User-Defined Operators 35.13. Operator Optimization Information 35.14. Interfacing Extensions To Indexes 35.15. 用C++擴(kuò)展 章36. 觸發(fā)器 36.1. 觸發(fā)器行為概述 36.3. 用 C 寫觸發(fā)器 36.2. 數(shù)據(jù)改變的可視性 36.4. 一個完整的例子 章37. 規(guī)則系統(tǒng) 37.1. The Query Tree 37.2. 視圖和規(guī)則系統(tǒng) 37.3. 在INSERT,UPDATE和DELETE上的規(guī)則 37.4. 規(guī)則和權(quán)限 37.5. 規(guī)則和命令狀態(tài) 37.6. 規(guī)則與觸發(fā)器得比較 章38. Procedural Languages 38.1. Installing Procedural Languages 章39. PL/pgSQL - SQL過程語言 39.1. 概述 39.2. PL/pgSQL的結(jié)構(gòu) 39.3. 聲明 39.4. 表達(dá)式 39.5. 基本語句 39.6. 控制結(jié)構(gòu) 39.7. 游標(biāo) 39.8. 錯誤和消息 39.9. 觸發(fā)器過程 39.10. PL/pgSQL Under the Hood 39.11. 開發(fā)PL/pgSQL的一些提示 39.12. 從OraclePL/SQL 進(jìn)行移植 章40. PL/Tcl - Tcl Procedural Language 40.1. Overview 40.2. PL/Tcl Functions and Arguments 40.3. Data Values in PL/Tcl 40.4. Global Data in PL/Tcl 40.5. Database Access from PL/Tcl 40.6. Trigger Procedures in PL/Tcl 40.7. Modules and the unknown command 40.8. Tcl Procedure Names 章41. PL/Perl - Perl Procedural Language 41.1. PL/Perl Functions and Arguments 41.2. Data Values in PL/Perl 41.3. Built-in Functions 41.4. Global Values in PL/Perl 41.6. PL/Perl Triggers 41.5. Trusted and Untrusted PL/Perl 41.7. PL/Perl Under the Hood 章42. PL/Python - Python Procedural Language 42.1. Python 2 vs. Python 3 42.2. PL/Python Functions 42.3. Data Values 42.4. Sharing Data 42.5. Anonymous Code Blocks 42.6. Trigger Functions 42.7. Database Access 42.8. Utility Functions 42.9. Environment Variables 章43. Server Programming Interface 43.1. Interface Functions Spi-spi-connect Spi-spi-finish Spi-spi-push Spi-spi-pop Spi-spi-execute Spi-spi-exec Spi-spi-execute-with-args Spi-spi-prepare Spi-spi-prepare-cursor Spi-spi-prepare-params Spi-spi-getargcount Spi-spi-getargtypeid Spi-spi-is-cursor-plan Spi-spi-execute-plan Spi-spi-execute-plan-with-paramlist Spi-spi-execp Spi-spi-cursor-open Spi-spi-cursor-open-with-args Spi-spi-cursor-open-with-paramlist Spi-spi-cursor-find Spi-spi-cursor-fetch Spi-spi-cursor-move Spi-spi-scroll-cursor-fetch Spi-spi-scroll-cursor-move Spi-spi-cursor-close Spi-spi-saveplan 43.2. Interface Support Functions Spi-spi-fname Spi-spi-fnumber Spi-spi-getvalue Spi-spi-getbinval Spi-spi-gettype Spi-spi-gettypeid Spi-spi-getrelname Spi-spi-getnspname 43.3. Memory Management Spi-spi-palloc Spi-realloc Spi-spi-pfree Spi-spi-copytuple Spi-spi-returntuple Spi-spi-modifytuple Spi-spi-freetuple Spi-spi-freetupletable Spi-spi-freeplan 43.4. Visibility of Data Changes 43.5. Examples VI. 參考手冊 I. SQL命令 Sql-abort Sql-alteraggregate Sql-alterconversion Sql-alterdatabase Sql-alterdefaultprivileges Sql-alterdomain Sql-alterforeigndatawrapper Sql-alterfunction Sql-altergroup Sql-alterindex Sql-alterlanguage Sql-alterlargeobject Sql-alteroperator Sql-alteropclass Sql-alteropfamily Sql-alterrole Sql-alterschema Sql-altersequence Sql-alterserver Sql-altertable Sql-altertablespace Sql-altertsconfig Sql-altertsdictionary Sql-altertsparser Sql-altertstemplate Sql-altertrigger Sql-altertype Sql-alteruser Sql-alterusermapping Sql-alterview Sql-analyze Sql-begin Sql-checkpoint Sql-close Sql-cluster Sql-comment Sql-commit Sql-commit-prepared Sql-copy Sql-createaggregate Sql-createcast Sql-createconstraint Sql-createconversion Sql-createdatabase Sql-createdomain Sql-createforeigndatawrapper Sql-createfunction Sql-creategroup Sql-createindex Sql-createlanguage Sql-createoperator Sql-createopclass Sql-createopfamily Sql-createrole Sql-createrule Sql-createschema Sql-createsequence Sql-createserver Sql-createtable Sql-createtableas Sql-createtablespace Sql-createtsconfig Sql-createtsdictionary Sql-createtsparser Sql-createtstemplate Sql-createtrigger Sql-createtype Sql-createuser Sql-createusermapping Sql-createview Sql-deallocate Sql-declare Sql-delete Sql-discard Sql-do Sql-dropaggregate Sql-dropcast Sql-dropconversion Sql-dropdatabase Sql-dropdomain Sql-dropforeigndatawrapper Sql-dropfunction Sql-dropgroup Sql-dropindex Sql-droplanguage Sql-dropoperator Sql-dropopclass Sql-dropopfamily Sql-drop-owned Sql-droprole Sql-droprule Sql-dropschema Sql-dropsequence Sql-dropserver Sql-droptable Sql-droptablespace Sql-droptsconfig Sql-droptsdictionary Sql-droptsparser Sql-droptstemplate Sql-droptrigger Sql-droptype Sql-dropuser Sql-dropusermapping Sql-dropview Sql-end Sql-execute Sql-explain Sql-fetch Sql-grant Sql-insert Sql-listen Sql-load Sql-lock Sql-move Sql-notify Sql-prepare Sql-prepare-transaction Sql-reassign-owned Sql-reindex Sql-release-savepoint Sql-reset Sql-revoke Sql-rollback Sql-rollback-prepared Sql-rollback-to Sql-savepoint Sql-select Sql-selectinto Sql-set Sql-set-constraints Sql-set-role Sql-set-session-authorization Sql-set-transaction Sql-show Sql-start-transaction Sql-truncate Sql-unlisten Sql-update Sql-vacuum Sql-values II. 客戶端應(yīng)用程序 App-clusterdb App-createdb App-createlang App-createuser App-dropdb App-droplang App-dropuser App-ecpg App-pgconfig App-pgdump App-pg-dumpall App-pgrestore App-psql App-reindexdb App-vacuumdb III. PostgreSQL服務(wù)器應(yīng)用程序 App-initdb App-pgcontroldata App-pg-ctl App-pgresetxlog App-postgres App-postmaster VII. 內(nèi)部 章44. PostgreSQL內(nèi)部概覽 44.1. 查詢路徑 44.2. 連接是如何建立起來的 44.3. 分析器階段 44.4. ThePostgreSQL規(guī)則系統(tǒng) 44.5. 規(guī)劃器/優(yōu)化器 44.6. 執(zhí)行器 章45. 系統(tǒng)表 45.1. 概述 45.2. pg_aggregate 45.3. pg_am 45.4. pg_amop 45.5. pg_amproc 45.6. pg_attrdef 45.7. pg_attribute 45.8. pg_authid 45.9. pg_auth_members 45.10. pg_cast 45.11. pg_class 45.12. pg_constraint 45.13. pg_conversion 45.14. pg_database 45.15. pg_db_role_setting 45.16. pg_default_acl 45.17. pg_depend 45.18. pg_description 45.19. pg_enum 45.20. pg_foreign_data_wrapper 45.21. pg_foreign_server 45.22. pg_index 45.23. pg_inherits 45.24. pg_language 45.25. pg_largeobject 45.26. pg_largeobject_metadata 45.27. pg_namespace 45.28. pg_opclass 45.29. pg_operator 45.30. pg_opfamily 45.31. pg_pltemplate 45.32. pg_proc 45.33. pg_rewrite 45.34. pg_shdepend 45.35. pg_shdescription 45.36. pg_statistic 45.37. pg_tablespace 45.38. pg_trigger 45.39. pg_ts_config 45.40. pg_ts_config_map 45.41. pg_ts_dict 45.42. pg_ts_parser 45.43. pg_ts_template 45.44. pg_type 45.45. pg_user_mapping 45.46. System Views 45.47. pg_cursors 45.48. pg_group 45.49. pg_indexes 45.50. pg_locks 45.51. pg_prepared_statements 45.52. pg_prepared_xacts 45.53. pg_roles 45.54. pg_rules 45.55. pg_settings 45.56. pg_shadow 45.57. pg_stats 45.58. pg_tables 45.59. pg_timezone_abbrevs 45.60. pg_timezone_names 45.61. pg_user 45.62. pg_user_mappings 45.63. pg_views 章46. Frontend/Backend Protocol 46.1. Overview 46.2. Message Flow 46.3. Streaming Replication Protocol 46.4. Message Data Types 46.5. Message Formats 46.6. Error and Notice Message Fields 46.7. Summary of Changes since Protocol 2.0 47. PostgreSQL Coding Conventions 47.1. Formatting 47.2. Reporting Errors Within the Server 47.3. Error Message Style Guide 章48. Native Language Support 48.1. For the Translator 48.2. For the Programmer 章49. Writing A Procedural Language Handler 章50. Genetic Query Optimizer 50.1. Query Handling as a Complex Optimization Problem 50.2. Genetic Algorithms 50.3. Genetic Query Optimization (GEQO) in PostgreSQL 50.4. Further Reading 章51. 索引訪問方法接口定義 51.1. 索引的系統(tǒng)表記錄 51.2. 索引訪問方法函數(shù) 51.3. 索引掃描 51.4. 索引鎖的考量 51.5. 索引唯一性檢查 51.6. 索引開銷估計函數(shù) 章52. GiST Indexes 52.1. Introduction 52.2. Extensibility 52.3. Implementation 52.4. Examples 52.5. Crash Recovery 章53. GIN Indexes 53.1. Introduction 53.2. Extensibility 53.3. Implementation 53.4. GIN tips and tricks 53.5. Limitations 53.6. Examples 章54. 數(shù)據(jù)庫物理存儲 54.1. 數(shù)據(jù)庫文件布局 54.2. TOAST 54.3. 自由空間映射 54.4. 可見映射 54.5. 數(shù)據(jù)庫分頁文件 章55. BKI后端接口 55.1. BKI 文件格式 55.2. BKI命令 55.3. 系統(tǒng)初始化的BKI文件的結(jié)構(gòu) 55.4. 例子 章56. 規(guī)劃器如何使用統(tǒng)計信息 56.1. 行預(yù)期的例子 VIII. 附錄 A. PostgreSQL錯誤代碼 B. 日期/時間支持 B.1. 日期/時間輸入解析 B.2. 日期/時間關(guān)鍵字 B.3. 日期/時間配置文件 B.4. 日期單位的歷史 C. SQL關(guān)鍵字 D. SQL Conformance D.1. Supported Features D.2. Unsupported Features E. 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characters

33.10. Informix compatibility mode

ecpg can be run in a so-called Informix compatibility mode. If this mode is active, it tries to behave as if it were the Informix precompiler for Informix E/SQL. Generally spoken this will allow you to use the dollar sign instead of the EXEC SQL primitive to introduce embedded SQL commands.:

$int j = 3;
$CONNECT TO :dbname;
$CREATE TABLE test(i INT PRIMARY KEY, j INT);
$INSERT INTO test(i, j) VALUES (7, :j);
$COMMIT;

There are two compatibility modes: INFORMIX, INFORMIX_SE

When linking programs that use this compatibility mode, remember to link against libcompat that is shipped with ECPG.

Besides the previously explained syntactic sugar, the Informix compatibility mode ports some functions for input, output and transformation of data as well as embedded SQL statements known from E/SQL to ECPG.

Informix compatibility mode is closely connected to the pgtypeslib library of ECPG. pgtypeslib maps SQL data types to data types within the C host program and most of the additional functions of the Informix compatibility mode allow you to operate on those C host program types. Note however that the extent of the compatibility is limited. It does not try to copy Informix behavior; it allows you to do more or less the same operations and gives you functions that have the same name and the same basic behavior but it is no drop-in replacement if you are using Informix at the moment. Moreover, some of the data types are different. For example, PostgreSQL's datetime and interval types do not know about ranges like for example YEAR TO MINUTE so you won't find support in ECPG for that either.

33.10.1. Additional types

The Informix-special "string" pseudo-type for storing right-trimmed character string data is now supported in Informix-mode without using typedef. In fact, in Informix-mode, ECPG refuses to process source files that contain typedef sometype string;

EXEC SQL BEGIN DECLARE SECTION;
string userid; /* this variable will contain trimmed data */
EXEC SQL END DECLARE SECTION;

EXEC SQL FETCH MYCUR INTO :userid;

33.10.2. Additional/missing embedded SQL statements

CLOSE DATABASE

This statement closes the current connection. In fact, this is a synonym for ECPG's DISCONNECT CURRENT.:

$CLOSE DATABASE;                /* close the current connection */
EXEC SQL CLOSE DATABASE;

FREE cursor_name

Due to the differences how ECPG works compared to Informix's ESQL/C (i.e. which steps are purely grammar transformations and which steps rely on the underlying run-time library) there is no FREE cursor_name statement in ECPG. This is because in ECPG, DECLARE CURSOR doesn't translate to a function call into the run-time library that uses to the cursor name. This means that there's no run-time bookkeeping of SQL cursors in the ECPG run-time library, only in the PostgreSQL server.

FREE statement_name

FREE statement_name is a synonym for DEALLOCATE PREPARE statement_name.

33.10.3. Informix-compatible SQLDA Descriptor Areas

Informix-compatible mode supports a different structure than the one described in Section 33.9.2. See below:

struct sqlvar_compat
{
        short   sqltype;
        int     sqllen;
        char       *sqldata;
        short      *sqlind;
        char       *sqlname;
        char       *sqlformat;
        short   sqlitype;
        short   sqlilen;
        char       *sqlidata;
        int     sqlxid;
        char       *sqltypename;
        short   sqltypelen;
        short   sqlownerlen;
        short   sqlsourcetype;
        char       *sqlownername;
        int     sqlsourceid;

        char       *sqlilongdata;
        int     sqlflags;
        void       *sqlreserved;
};

struct sqlda_compat
{
        short           sqld;
        struct sqlvar_compat *sqlvar;
        char            desc_name[19];
        short           desc_occ;
        struct sqlda_compat *desc_next;
        void               *reserved;
};

typedef struct sqlvar_compat    sqlvar_t;
typedef struct sqlda_compat     sqlda_t;

The global properties are:

sqld

The number of fields in the SQLDA descriptor.

sqlvar

Pointer to the per-field properties.

desc_name

Unused, filled with zero-bytes.

desc_occ

Size of the allocated structure.

desc_next

Pointer to the next SQLDA structure if the result set contains more than one records.

reserved

Unused pointer, contains NULL. Kept for Informix-compatibility.

The per-field properties are below, they are stored in the sqlvar array:

sqltype

Type of the field. Constants are in sqltypes.h

sqllen

Length of the field data.

sqldata

Pointer to the field data. The pointer is of char * type, the data pointed by it is in a binary format. Example:

int intval; 

switch (sqldata->sqlvar[i].sqltype)
{
    case SQLINTEGER:
        intval = *(int *)sqldata->sqlvar[i].sqldata;
        break;
  ...
}

sqlind

Pointer to the NULL indicator. If returned by DESCRIBE or FETCH then it's always a valid pointer. If used as input for EXECUTE ... USING sqlda; then NULL-pointer value means that the value for this field is non-NULL. Otherwise a valid pointer and sqlitype has to be properly set. Example:

if (*(int2 *)sqldata->sqlvar[i].sqlind != 0)
    printf("value is NULL\n");

sqlname

Name of the field. 0-terminated string.

sqlformat

Reserved in Informix, value of PQfformat() for the field.

sqlitype

Type of the NULL indicator data. It's always SQLSMINT when returning data from the server. When the SQLDA is used for a parametrized query, the data is treated according to the set type.

sqlilen

Length of the NULL indicator data.

sqlxid

Extended type of the field, result of PQftype().

sqltypename
sqltypelen
sqlownerlen
sqlsourcetype
sqlownername
sqlsourceid
sqlflags
sqlreserved

Unused.

sqlilongdata

It equals to sqldata if sqllen is larger than 32KB.

Example:

EXEC SQL INCLUDE sqlda.h;

    sqlda_t        *sqlda; /* This doesn't need to be under embedded DECLARE SECTION */

    EXEC SQL BEGIN DECLARE SECTION;
    char *prep_stmt = "select * from table1";
    int i;
    EXEC SQL END DECLARE SECTION;

    ...

    EXEC SQL PREPARE mystmt FROM :prep_stmt;

    EXEC SQL DESCRIBE mystmt INTO sqlda;

    printf("# of fields: %d\n", sqlda->sqld);
    for (i = 0; i < sqlda->sqld; i++)
      printf("field %d: \"%s\"\n", sqlda->sqlvar[i]->sqlname);

    EXEC SQL DECLARE mycursor CURSOR FOR mystmt;
    EXEC SQL OPEN mycursor;
    EXEC SQL WHENEVER NOT FOUND GOTO out;

    while (1)
    {
      EXEC SQL FETCH mycursor USING sqlda;
    }

    EXEC SQL CLOSE mycursor;

    free(sqlda); /* The main structure is all to be free(),
                  * sqlda and sqlda->sqlvar is in one allocated area */

For more information, see the sqlda.h header and the src/interfaces/ecpg/test/compat_informix/sqlda.pgc regression test.

33.10.4. Additional functions

decadd

Add two decimal type values.

int decadd(decimal *arg1, decimal *arg2, decimal *sum);

The function receives a pointer to the first operand of type decimal (arg1), a pointer to the second operand of type decimal (arg2) and a pointer to a value of type decimal that will contain the sum (sum). On success, the function returns 0. ECPG_INFORMIX_NUM_OVERFLOW is returned in case of overflow and ECPG_INFORMIX_NUM_UNDERFLOW in case of underflow. -1 is returned for other failures and errno is set to the respective errno number of the pgtypeslib.

deccmp

Compare two variables of type decimal.

int deccmp(decimal *arg1, decimal *arg2);

The function receives a pointer to the first decimal value (arg1), a pointer to the second decimal value (arg2) and returns an integer value that indicates which is the bigger value.

  • 1, if the value that arg1 points to is bigger than the value that var2 points to

  • -1, if the value that arg1 points to is smaller than the value that arg2 points to

  • 0, if the value that arg1 points to and the value that arg2 points to are equal

deccopy

Copy a decimal value.

void deccopy(decimal *src, decimal *target);

The function receives a pointer to the decimal value that should be copied as the first argument (src) and a pointer to the target structure of type decimal (target) as the second argument.

deccvasc

Convert a value from its ASCII representation into a decimal type.

int deccvasc(char *cp, int len, decimal *np);

The function receives a pointer to string that contains the string representation of the number to be converted (cp) as well as its length len. np is a pointer to the decimal value that saves the result of the operation.

Valid formats are for example: -2, .794, +3.44, 592.49E07 or -32.84e-4.

The function returns 0 on success. If overflow or underflow occurred, ECPG_INFORMIX_NUM_OVERFLOW or ECPG_INFORMIX_NUM_UNDERFLOW is returned. If the ASCII representation could not be parsed, ECPG_INFORMIX_BAD_NUMERIC is returned or ECPG_INFORMIX_BAD_EXPONENT if this problem occurred while parsing the exponent.

deccvdbl

Convert a value of type double to a value of type decimal.

int deccvdbl(double dbl, decimal *np);

The function receives the variable of type double that should be converted as its first argument (dbl). As the second argument (np), the function receives a pointer to the decimal variable that should hold the result of the operation.

The function returns 0 on success and a negative value if the conversion failed.

deccvint

Convert a value of type int to a value of type decimal.

int deccvint(int in, decimal *np);

The function receives the variable of type int that should be converted as its first argument (in). As the second argument (np), the function receives a pointer to the decimal variable that should hold the result of the operation.

The function returns 0 on success and a negative value if the conversion failed.

deccvlong

Convert a value of type long to a value of type decimal.

int deccvlong(long lng, decimal *np);

The function receives the variable of type long that should be converted as its first argument (lng). As the second argument (np), the function receives a pointer to the decimal variable that should hold the result of the operation.

The function returns 0 on success and a negative value if the conversion failed.

decdiv

Divide two variables of type decimal.

int decdiv(decimal *n1, decimal *n2, decimal *result);

The function receives pointers to the variables that are the first (n1) and the second (n2) operands and calculates n1/n2. result is a pointer to the variable that should hold the result of the operation.

On success, 0 is returned and a negative value if the division fails. If overflow or underflow occurred, the function returns ECPG_INFORMIX_NUM_OVERFLOW or ECPG_INFORMIX_NUM_UNDERFLOW respectively. If an attempt to divide by zero is observed, the function returns ECPG_INFORMIX_DIVIDE_ZERO.

decmul

Multiply two decimal values.

int decmul(decimal *n1, decimal *n2, decimal *result);

The function receives pointers to the variables that are the first (n1) and the second (n2) operands and calculates n1*n2. result is a pointer to the variable that should hold the result of the operation.

On success, 0 is returned and a negative value if the multiplication fails. If overflow or underflow occurred, the function returns ECPG_INFORMIX_NUM_OVERFLOW or ECPG_INFORMIX_NUM_UNDERFLOW respectively.

decsub

Subtract one decimal value from another.

int decsub(decimal *n1, decimal *n2, decimal *result);

The function receives pointers to the variables that are the first (n1) and the second (n2) operands and calculates n1-n2. result is a pointer to the variable that should hold the result of the operation.

On success, 0 is returned and a negative value if the subtraction fails. If overflow or underflow occurred, the function returns ECPG_INFORMIX_NUM_OVERFLOW or ECPG_INFORMIX_NUM_UNDERFLOW respectively.

dectoasc

Convert a variable of type decimal to its ASCII representation in a C char* string.

int dectoasc(decimal *np, char *cp, int len, int right)

The function receives a pointer to a variable of type decimal (np) that it converts to its textual representation. cp is the buffer that should hold the result of the operation. The parameter right specifies, how many digits right of the decimal point should be included in the output. The result will be rounded to this number of decimal digits. Setting right to -1 indicates that all available decimal digits should be included in the output. If the length of the output buffer, which is indicated by len is not sufficient to hold the textual representation including the trailing NUL character, only a single * character is stored in the result and -1 is returned.

The function returns either -1 if the buffer cp was too small or ECPG_INFORMIX_OUT_OF_MEMORY if memory was exhausted.

dectodbl

Convert a variable of type decimal to a double.

int dectodbl(decimal *np, double *dblp);

The function receives a pointer to the decimal value to convert (np) and a pointer to the double variable that should hold the result of the operation (dblp).

On success, 0 is returned and a negative value if the conversion failed.

dectoint

Convert a variable to type decimal to an integer.

int dectoint(decimal *np, int *ip);

The function receives a pointer to the decimal value to convert (np) and a pointer to the integer variable that should hold the result of the operation (ip).

On success, 0 is returned and a negative value if the conversion failed. If an overflow occurred, ECPG_INFORMIX_NUM_OVERFLOW is returned.

Note that the ECPG implementation differs from the Informix implementation. Informix limits an integer to the range from -32767 to 32767, while the limits in the ECPG implementation depend on the architecture (-INT_MAX .. INT_MAX).

dectolong

Convert a variable to type decimal to a long integer.

int dectolong(decimal *np, long *lngp);

The function receives a pointer to the decimal value to convert (np) and a pointer to the long variable that should hold the result of the operation (lngp).

On success, 0 is returned and a negative value if the conversion failed. If an overflow occurred, ECPG_INFORMIX_NUM_OVERFLOW is returned.

Note that the ECPG implementation differs from the Informix implementation. Informix limits a long integer to the range from -2,147,483,647 to 2,147,483,647, while the limits in the ECPG implementation depend on the architecture (-LONG_MAX .. LONG_MAX).

rdatestr

Converts a date to a C char* string.

int rdatestr(date d, char *str);

The function receives two arguments, the first one is the date to convert (d and the second one is a pointer to the target string. The output format is always yyyy-mm-dd, so you need to allocate at least 11 bytes (including the NUL-terminator) for the string.

The function returns 0 on success and a negative value in case of error.

Note that ECPG's implementation differs from the Informix implementation. In Informix the format can be influenced by setting environment variables. In ECPG however, you cannot change the output format.

rstrdate

Parse the textual representation of a date.

int rstrdate(char *str, date *d);

The function receives the textual representation of the date to convert (str) and a pointer to a variable of type date (d). This function does not allow you to specify a format mask. It uses the default format mask of Informix which is mm/dd/yyyy. Internally, this function is implemented by means of rdefmtdate. Therefore, rstrdate is not faster and if you have the choice you should opt for rdefmtdate which allows you to specify the format mask explicitly.

The function returns the same values as rdefmtdate.

rtoday

Get the current date.

void rtoday(date *d);

The function receives a pointer to a date variable (d) that it sets to the current date.

Internally this function uses the PGTYPESdate_today function.

rjulmdy

Extract the values for the day, the month and the year from a variable of type date.

int rjulmdy(date d, short mdy[3]);

The function receives the date d and a pointer to an array of 3 short integer values mdy. The variable name indicates the sequential order: mdy[0] will be set to contain the number of the month, mdy[1] will be set to the value of the day and mdy[2] will contain the year.

The function always returns 0 at the moment.

Internally the function uses the PGTYPESdate_julmdy function.

rdefmtdate

Use a format mask to convert a character string to a value of type date.

int rdefmtdate(date *d, char *fmt, char *str);

The function receives a pointer to the date value that should hold the result of the operation (d), the format mask to use for parsing the date (fmt) and the C char* string containing the textual representation of the date (str). The textual representation is expected to match the format mask. However you do not need to have a 1:1 mapping of the string to the format mask. The function only analyzes the sequential order and looks for the literals yy or yyyy that indicate the position of the year, mm to indicate the position of the month and dd to indicate the position of the day.

The function returns the following values:

  • 0 - The function terminated successfully.

  • ECPG_INFORMIX_ENOSHORTDATE - The date does not contain delimiters between day, month and year. In this case the input string must be exactly 6 or 8 bytes long but isn't.

  • ECPG_INFORMIX_ENOTDMY - The format string did not correctly indicate the sequential order of year, month and day.

  • ECPG_INFORMIX_BAD_DAY - The input string does not contain a valid day.

  • ECPG_INFORMIX_BAD_MONTH - The input string does not contain a valid month.

  • ECPG_INFORMIX_BAD_YEAR - The input string does not contain a valid year.

Internally this function is implemented to use the PGTYPESdate_defmt_asc function. See the reference there for a table of example input.

rfmtdate

Convert a variable of type date to its textual representation using a format mask.

int rfmtdate(date d, char *fmt, char *str);

The function receives the date to convert (d), the format mask (fmt) and the string that will hold the textual representation of the date (str).

On success, 0 is returned and a negative value if an error occurred.

Internally this function uses the PGTYPESdate_fmt_asc function, see the reference there for examples.

rmdyjul

Create a date value from an array of 3 short integers that specify the day, the month and the year of the date.

int rmdyjul(short mdy[3], date *d);

The function receives the array of the 3 short integers (mdy) and a pointer to a variable of type date that should hold the result of the operation.

Currently the function returns always 0.

Internally the function is implemented to use the function PGTYPESdate_mdyjul.

rdayofweek

Return a number representing the day of the week for a date value.

int rdayofweek(date d);

The function receives the date variable d as its only argument and returns an integer that indicates the day of the week for this date.

  • 0 - Sunday

  • 1 - Monday

  • 2 - Tuesday

  • 3 - Wednesday

  • 4 - Thursday

  • 5 - Friday

  • 6 - Saturday

Internally the function is implemented to use the function PGTYPESdate_dayofweek.

dtcurrent

Retrieve the current timestamp.

void dtcurrent(timestamp *ts);

The function retrieves the current timestamp and saves it into the timestamp variable that ts points to.

dtcvasc

Parses a timestamp from its textual representation into a timestamp variable.

int dtcvasc(char *str, timestamp *ts);

The function receives the string to parse (str) and a pointer to the timestamp variable that should hold the result of the operation (ts).

The function returns 0 on success and a negative value in case of error.

Internally this function uses the PGTYPEStimestamp_from_asc function. See the reference there for a table with example inputs.

dtcvfmtasc

Parses a timestamp from its textual representation using a format mask into a timestamp variable.

dtcvfmtasc(char *inbuf, char *fmtstr, timestamp *dtvalue)

The function receives the string to parse (inbuf), the format mask to use (fmtstr) and a pointer to the timestamp variable that should hold the result of the operation (dtvalue).

This function is implemented by means of the PGTYPEStimestamp_defmt_asc function. See the documentation there for a list of format specifiers that can be used.

The function returns 0 on success and a negative value in case of error.

dtsub

Subtract one timestamp from another and return a variable of type interval.

int dtsub(timestamp *ts1, timestamp *ts2, interval *iv);

The function will subtract the timestamp variable that ts2 points to from the timestamp variable that ts1 points to and will store the result in the interval variable that iv points to.

Upon success, the function returns 0 and a negative value if an error occurred.

dttoasc

Convert a timestamp variable to a C char* string.

int dttoasc(timestamp *ts, char *output);

The function receives a pointer to the timestamp variable to convert (ts) and the string that should hold the result of the operation output). It converts ts to its textual representation according to the SQL standard, which is be YYYY-MM-DD HH:MM:SS.

Upon success, the function returns 0 and a negative value if an error occurred.

dttofmtasc

Convert a timestamp variable to a C char* using a format mask.

int dttofmtasc(timestamp *ts, char *output, int str_len, char *fmtstr);

The function receives a pointer to the timestamp to convert as its first argument (ts), a pointer to the output buffer (output), the maximal length that has been allocated for the output buffer (str_len) and the format mask to use for the conversion (fmtstr).

Upon success, the function returns 0 and a negative value if an error occurred.

Internally, this function uses the PGTYPEStimestamp_fmt_asc function. See the reference there for information on what format mask specifiers can be used.

intoasc

Convert an interval variable to a C char* string.

int intoasc(interval *i, char *str);

The function receives a pointer to the interval variable to convert (i) and the string that should hold the result of the operation str). It converts i to its textual representation according to the SQL standard, which is be YYYY-MM-DD HH:MM:SS.

Upon success, the function returns 0 and a negative value if an error occurred.

rfmtlong

Convert a long integer value to its textual representation using a format mask.

int rfmtlong(long lng_val, char *fmt, char *outbuf);

The function receives the long value lng_val, the format mask fmt and a pointer to the output buffer outbuf. It converts the long value according to the format mask to its textual representation.

The format mask can be composed of the following format specifying characters:

  • * (asterisk) - if this position would be blank otherwise, fill it with an asterisk.

  • & (ampersand) - if this position would be blank otherwise, fill it with a zero.

  • # - turn leading zeroes into blanks.

  • < - left-justify the number in the string.

  • , (comma) - group numbers of four or more digits into groups of three digits separated by a comma.

  • . (period) - this character separates the whole-number part of the number from the fractional part.

  • - (minus) - the minus sign appears if the number is a negative value.

  • + (plus) - the plus sign appears if the number is a positive value.

  • ( - this replaces the minus sign in front of the negative number. The minus sign will not appear.

  • ) - this character replaces the minus and is printed behind the negative value.

  • $ - the currency symbol.

rupshift

Convert a string to upper case.

void rupshift(char *str);

The function receives a pointer to the string and transforms every lower case character to upper case.

byleng

Return the number of characters in a string without counting trailing blanks.

int byleng(char *str, int len);

The function expects a fixed-length string as its first argument (str) and its length as its second argument (len). It returns the number of significant characters, that is the length of the string without trailing blanks.

ldchar

Copy a fixed-length string into a null-terminated string.

void ldchar(char *src, int len, char *dest);

The function receives the fixed-length string to copy (src), its length (len) and a pointer to the destination memory (dest). Note that you need to reserve at least len+1 bytes for the string that dest points to. The function copies at most len bytes to the new location (less if the source string has trailing blanks) and adds the null-terminator.

rgetmsg

int rgetmsg(int msgnum, char *s, int maxsize);

This function exists but is not implemented at the moment!

rtypalign

int rtypalign(int offset, int type);

This function exists but is not implemented at the moment!

rtypmsize

int rtypmsize(int type, int len);

This function exists but is not implemented at the moment!

rtypwidth

int rtypwidth(int sqltype, int sqllen);

This function exists but is not implemented at the moment!

rsetnull

Set a variable to NULL.

int rsetnull(int t, char *ptr);

The function receives an integer that indicates the type of the variable and a pointer to the variable itself that is casted to a C char* pointer.

The following types exist:

  • CCHARTYPE - For a variable of type char or char*

  • CSHORTTYPE - For a variable of type short int

  • CINTTYPE - For a variable of type int

  • CBOOLTYPE - For a variable of type boolean

  • CFLOATTYPE - For a variable of type float

  • CLONGTYPE - For a variable of type long

  • CDOUBLETYPE - For a variable of type double

  • CDECIMALTYPE - For a variable of type decimal

  • CDATETYPE - For a variable of type date

  • CDTIMETYPE - For a variable of type timestamp

Here is an example of a call to this function:

$char c[] = "abc       ";
$short s = 17;
$int i = -74874;

rsetnull(CCHARTYPE, (char *) c);
rsetnull(CSHORTTYPE, (char *) &s);
rsetnull(CINTTYPE, (char *) &i);

risnull

Test if a variable is NULL.

int risnull(int t, char *ptr);

The function receives the type of the variable to test (t) as well a pointer to this variable (ptr). Note that the latter needs to be casted to a char*. See the function rsetnull for a list of possible variable types.

Here is an example of how to use this function:

$char c[] = "abc       ";
$short s = 17;
$int i = -74874;

risnull(CCHARTYPE, (char *) c);
risnull(CSHORTTYPE, (char *) &s);
risnull(CINTTYPE, (char *) &i);

33.10.5. Additional constants

Note that all constants here describe errors and all of them are defined to represent negative values. In the descriptions of the different constants you can also find the value that the constants represent in the current implementation. However you should not rely on this number. You can however rely on the fact all of them are defined to represent negative values.

ECPG_INFORMIX_NUM_OVERFLOW

Functions return this value if an overflow occurred in a calculation. Internally it is defined to -1200 (the Informix definition).

ECPG_INFORMIX_NUM_UNDERFLOW

Functions return this value if an underflow occurred in a calculation. Internally it is defined to -1201 (the Informix definition).

ECPG_INFORMIX_DIVIDE_ZERO

Functions return this value if an attempt to divide by zero is observed. Internally it is defined to -1202 (the Informix definition).

ECPG_INFORMIX_BAD_YEAR

Functions return this value if a bad value for a year was found while parsing a date. Internally it is defined to -1204 (the Informix definition).

ECPG_INFORMIX_BAD_MONTH

Functions return this value if a bad value for a month was found while parsing a date. Internally it is defined to -1205 (the Informix definition).

ECPG_INFORMIX_BAD_DAY

Functions return this value if a bad value for a day was found while parsing a date. Internally it is defined to -1206 (the Informix definition).

ECPG_INFORMIX_ENOSHORTDATE

Functions return this value if a parsing routine needs a short date representation but did not get the date string in the right length. Internally it is defined to -1209 (the Informix definition).

ECPG_INFORMIX_DATE_CONVERT

Functions return this value if Internally it is defined to -1210 (the Informix definition).

ECPG_INFORMIX_OUT_OF_MEMORY

Functions return this value if Internally it is defined to -1211 (the Informix definition).

ECPG_INFORMIX_ENOTDMY

Functions return this value if a parsing routine was supposed to get a format mask (like mmddyy) but not all fields were listed correctly. Internally it is defined to -1212 (the Informix definition).

ECPG_INFORMIX_BAD_NUMERIC

Functions return this value either if a parsing routine cannot parse the textual representation for a numeric value because it contains errors or if a routine cannot complete a calculation involving numeric variables because at least one of the numeric variables is invalid. Internally it is defined to -1213 (the Informix definition).

ECPG_INFORMIX_BAD_EXPONENT

Functions return this value if Internally it is defined to -1216 (the Informix definition).

ECPG_INFORMIX_BAD_DATE

Functions return this value if Internally it is defined to -1218 (the Informix definition).

ECPG_INFORMIX_EXTRA_CHARS

Functions return this value if Internally it is defined to -1264 (the Informix definition).

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