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Customized Options19.16. Customized Options
This feature was designed to allow parameters not normally known to PostgreSQL to be added by add-on modules (such as procedural languages). This allows extension m…Customized Options
Cycle Detection7.8.2.2. Cycle Detection
When working with recursive queries it is important to be sure that the recursive part of the query will eventually return no tuples, or else the query will loop ind…Cycle Detection
Cygwin17.7.1. Cygwin
PostgreSQL can be built using Cygwin, a Linux-like environment for Windows, but that method is inferior to the native Windows build and running a server under Cygwin is no lon…Cygwin
Daitch-Mokotoff SoundexF.16.2. Daitch-Mokotoff Soundex
Like the original Soundex system, Daitch-Mokotoff Soundex matches similar-sounding names by converting them to the same code. However, Daitch-Mokotoff Soundex…Daitch-Mokotoff Soundex
Data Checksums28.2. Data Checksums
By default, data pages are protected by checksums, but this can optionally be disabled for a cluster. When enabled, each data page includes a checksum that is updated wh…Data Checksums
Data Consistency Checks at the Application Level13.4. Data Consistency Checks at the Application Level
It is very difficult to enforce business rules regarding data integrity using Read Committed transactions because the view of the data …Data Consistency Checks at the Application Level
Data DefinitionChapter 5. Data Definition
This chapter covers how one creates the database structures that will hold one's data. In a relational database, the raw data is stored in tables, so the majority …Data Definition
Data File Format68.2.1. Data File Format
Each .dat file contains Perl data structure literals that are simply eval'd to produce an in-memory data structure consisting of an array of hash references, one per…Data File Format
Data ManipulationChapter 6. Data Manipulation
The previous chapter discussed how to create tables and other structures to hold your data. Now it is time to fill the tables with data. This chapter covers how …Data Manipulation
Data Type Formatting Functions9.8. Data Type Formatting Functions
The PostgreSQL formatting functions provide a powerful set of tools for converting various data types (date/time, integer, floating point, numeric) to for…Data Type Formatting Functions
Data Type Mapping44.2.1. Data Type Mapping
When a PL/Python function is called, its arguments are converted from their PostgreSQL data type to a corresponding Python type:
PostgreSQL boolean is converted to …Data Type Mapping
Data TypesChapter 8. Data Types
PostgreSQL has a rich set of native data types available to users. Users can add new types to PostgreSQL using the CREATE TYPE command.
Table 8.1 shows all the built-in…Data Types
Data Types35.2. Data Types
The columns of the information schema views use special data types that are defined in the information schema. These are defined as simple domains over ordinary built-in typ…Data Types
Data TypesF.20.1. Data Types
Table F.10 shows the data types provided by the isn module.
Table F.10. isn Data Types Data Type Description EAN13 European Article Numbers, always displayed in the EAN13 …Data Types
Data TypesE.6.3.3. Data Types
Improve Unicode full case mapping and conversion (Jeff Davis) § § This adds the ability to do conditional and title case mapping, and case map single characters to multip…Data Types
Data Validity Checking Functions9.27.7. Data Validity Checking Functions
The functions shown in Table 9.83 can be helpful for checking validity of proposed input data.
Table 9.83. Data Validity Checking Functions Function …Data Validity Checking Functions
Data Values44.2. Data Values
Generally speaking, the aim of PL/Python is to provide a “natural” mapping between the PostgreSQL and the Python worlds. This informs the data mapping rules described below…Data Values
Data Values in PL/Perl43.2. Data Values in PL/Perl
The argument values supplied to a PL/Perl function's code are simply the input arguments converted to text form (just as if they had been displayed by a SELECT s…Data Values in PL/Perl
Data Values in PL/Tcl42.3. Data Values in PL/Tcl
The argument values supplied to a PL/Tcl function's code are simply the input arguments converted to text form (just as if they had been displayed by a SELECT sta…Data Values in PL/Tcl
Data-Modifying Statements in WITH7.8.4. Data-Modifying Statements in WITH
You can use data-modifying statements (INSERT, UPDATE, DELETE, or MERGE) in WITH. This allows you to perform several different operations in the same…Data-Modifying Statements in WITH
Data-Modifying Statements in WITHData-Modifying Statements in WITH
PostgreSQL allows INSERT, UPDATE, DELETE, and MERGE to be used as WITH queries. This is not found in the SQL standard.Data-Modifying Statements in WITH
data_type_privileges35.20. data_type_privileges
The view data_type_privileges identifies all data type descriptors that the current user has access to, by way of being the owner of the described object or havin…data_type_privileges
Database Access44.6. Database Access
The PL/Python language module automatically imports a Python module called plpy. The functions and constants in this module are available to you in the Python code as p…Database Access
Database Access from PL/Perl43.3.1. Database Access from PL/Perl
Access to the database itself from your Perl function can be done via the following functions:
spi_exec_query(query [, limit])
spi_exec_query executes an…Database Access from PL/Perl
Database Access from PL/Tcl42.5. Database Access from PL/Tcl
In this section, we follow the usual Tcl convention of using question marks, rather than brackets, to indicate an optional element in a syntax synopsis. The…Database Access from PL/Tcl
Database Access Functions44.6.1. Database Access Functions
The plpy module provides several functions to execute database commands:
plpy.execute(query [, limit])
Calling plpy.execute with a query string and an optio…Database Access Functions
Database Configuration22.4. Database Configuration
Recall from Chapter 19 that the PostgreSQL server provides a large number of run-time configuration variables. You can set database-specific default values for m…Database Configuration
Database Connection Control Functions32.1. Database Connection Control Functions
The following functions deal with making a connection to a PostgreSQL backend server. An application program can have several backend connections …Database Connection Control Functions
Database File Layout66.1. Database File Layout
This section describes the storage format at the level of files and directories.
Traditionally, the configuration and data files used by a database cluster are sto…Database File Layout
Database Object Management Functions9.28.7. Database Object Management Functions
The functions shown in Table 9.102 calculate the disk space usage of database objects, or assist in presentation or understanding of usage result…Database Object Management Functions
Database Page Layout66.6. Database Page Layout
This section provides an overview of the page format used within PostgreSQL tables and indexes.[19] Sequences and TOAST tables are formatted just like a regular ta…Database Page Layout
Database Physical StorageChapter 66. Database Physical Storage
This chapter provides an overview of the physical storage format used by PostgreSQL databases.Database Physical Storage
Database Roles21.1. Database Roles
Database roles are conceptually completely separate from operating system users. In practice it might be convenient to maintain a correspondence, but this is not require…Database Roles
Database RolesChapter 21. Database Roles
PostgreSQL manages database access permissions using the concept of roles. A role can be thought of as either a database user, or a group of database users, depend…Database Roles
Date and Time Differences31.2.3. Date and Time Differences
Most of the date and time results are dependent on the time zone environment. The reference files are generated for time zone America/Los_Angeles, and there…Date and Time Differences
Date/Time Configuration FilesB.4. Date/Time Configuration Files
Since timezone abbreviations are not well standardized, PostgreSQL provides a means to customize the set of abbreviations accepted in datetime input. There…Date/Time Configuration Files
Date/Time Functions and Operators9.9. Date/Time Functions and Operators
Table 9.33 shows the available functions for date/time value processing, with details appearing in the following subsections. Table 9.32 illustrates th…Date/Time Functions and Operators
Date/Time Input8.5.1. Date/Time Input
Date and time input is accepted in almost any reasonable format, including ISO 8601, SQL-compatible, traditional POSTGRES, and others. For some formats, ordering of da…Date/Time Input
Date/Time Input InterpretationB.1. Date/Time Input Interpretation
Date/time input strings are decoded using the following procedure.
Break the input string into tokens and categorize each token as a string, time, time zo…Date/Time Input Interpretation
Date/Time Key WordsB.3. Date/Time Key Words
Table B.1 shows the tokens that are recognized as names of months.
Table B.1. Month Names Month Abbreviations January Jan February Feb March Mar April Apr May June J…Date/Time Key Words
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