PostgreSQL: The world's most advanced open source database
The PostgreSQL Global Development Group today announced the release of PostgreSQL 17, the latest version of the world's most advanced open source database. PostgreSQL 17 builds on decades of open source development, improving its performance and scalability while adapting to emergent data access and storage patterns.
PostgreSQL: Documentation: 17: psql
2024年9月26日 · Description. psql is a terminal-based front-end to PostgreSQL. It enables you to type in queries interactively, issue them to PostgreSQL, and see the query results. Alternatively, input can be from a file or from command line arguments.
9.9. Date/Time Functions and Operators - PostgreSQL
2024年9月26日 · Table 9.33 shows the available functions for date/time value processing, with details appearing in the following subsections. Table 9.32 illustrates the behaviors of the basic arithmetic operators (+, *, etc.).For formatting functions, refer to Section 9.8.You should be familiar with the background information on date/time data types from Section 8.5.
PostgreSQL: Documentation: 17: Chapter 8. Data Types
2024年9月26日 · 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 general-purpose data types. Most of the alternative names listed in the “ Aliases ” column are the names used internally by PostgreSQL for historical reasons. In addition, some internally …
PostgreSQL: Documentation: 17: 8.1. Numeric Types
2024年9月26日 · The type numeric can store numbers with a very large number of digits. It is especially recommended for storing monetary amounts and other quantities where exactness is required. Calculations with numeric values yield exact results where possible, e.g., addition, subtraction, multiplication. However, calculations on numeric values are very slow compared …
9.4. String Functions and Operators - PostgreSQL
2024年9月26日 · 9.4.1. format. This section describes functions and operators for examining and manipulating string values. Strings in this context include values of the types character, character varying, and text. Except where noted, these functions and operators are declared to accept and return type text. They will interchangeably accept character varying ...
9.8. Data Type Formatting Functions - PostgreSQL
2024年9月26日 · The PostgreSQL formatting functions provide a powerful set of tools for converting various data types (date/time, integer, floating point, numeric) to formatted strings and for converting from formatted strings to specific data types. Table 9.26 lists them. These functions all follow a common calling convention: the first argument is the value to be formatted and the …
PostgreSQL: Documentation: 17: ALTER TABLE
2024年9月26日 · Description. ALTER TABLE changes the definition of an existing table. There are several subforms described below. Note that the lock level required may differ for each subform. An ACCESS EXCLUSIVE lock is acquired unless explicitly noted. When multiple subcommands are given, the lock acquired will be the strictest one required by any subcommand.
PostgreSQL: Documentation: 17: pg_dump
2024年9月26日 · Description. pg_dump is a utility for backing up a PostgreSQL database. It makes consistent backups even if the database is being used concurrently. pg_dump does not block other users accessing the database (readers or …
9.16. JSON Functions and Operators - PostgreSQL
2024年9月26日 · the SQL/JSON query functions. To provide native support for JSON data types within the SQL environment, PostgreSQL implements the SQL/JSON data model. This model comprises sequences of items. Each item can hold SQL scalar values, with an additional SQL/JSON null value, and composite data structures that use JSON arrays and objects. The …