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notify_nowExtensionsExtensionsFeatures · ExtensionsPostgreSQL Extension to send multiple responses from one SQL Query using LISTEN/NOFITY API async response dynamic result set json listen multi result notify notify_now Features npmExtensionsExtensionsFeatures · ExtensionsSchema and tables for tracking npm package metadata and daily download counts. npm Features nr_modelExtensionsExtensionsAI and vectors · ExtensionsAI-powered Autonomous Data System aixdb database nr_model AI and vectors ntextExtensionsExtensionsData types · ExtensionsJapanese normalized-comparison text type for UTF-8 strings ntext Data types NULLSQL CommandsPG18CREATE TABLE › Compatibility › NULL “Constraint”“Constraint” The NULL “constraint” (actually a non-constraint) is a PostgreSQL extension to the SQL standard that is included for compatibility with some other database systems (and for symm… NULL HandlingManual ChaptersPG18pgcrypto — cryptographic functionsAs is standard in SQL, all functions return NULL, if any of the arguments are NULL. This may create security risks on careless usage. NULL “Constraint”Manual ChaptersPG18CREATE TABLEThe NULL “constraint” (actually a non-constraint) is a PostgreSQL extension to the SQL standard that is included for compatibility with some other database systems (and for symmetry with the… Null, NoneManual ChaptersPG18Data ValuesIf an SQL null value is passed to a function, the argument value will appear as None in Python. For example, the function definition of pymax shown in Section 44.1 will return the wrong answ… NULLIFSQL CommandsPG18Conditional Expressions › NULLIF# NULLIF(value1, value2) The NULLIF function returns a null value if value1 equals value2; otherwise it returns value1. This can be used to perform the inverse operation of the COALESCE exam… NULLIFManual ChaptersPG18Conditional Expressions(value1, value2) The NULLIF function returns a null value if value1 equals value2; otherwise it returns value1. This can be used to perform the inverse operation of the COALESCE example give… numberExtensionsExtensionsData types · ExtensionsVariable-width integer data type for PostgreSQL datatype integer postgresql-number Data types numeralExtensionsExtensionsData types · Extensionsdatatypes extension numeral Data types Numeric ConstantsManual ChaptersPG18Lexical Structureare accepted in these general forms: digits digits.[digits][e[+-]digits] [digits].digits[e[+-]digits] digitse[+-]digits where digits is one or more decimal digits (0 through 9). At least one… Numeric TypesManual ChaptersPG18consist of two-, four-, and eight-byte integers, four- and eight-byte floating-point numbers, and selectable-precision decimals. Table 8.2 lists the available types. Table 8.2. Numeric Types… numeric, decimalManual ChaptersPG18Using Host VariablesThe handling of the numeric and decimal types is similar to the interval type: It requires defining a pointer, allocating some memory space on the heap, and accessing the variable using the … numeric_domainsExtensionsExtensionsData types · ExtensionsCustom numeric domains for PostgreSQL domain latitude-longitude numeric validation numeric_domains Data types numhstoreExtensionsExtensionsData types · ExtensionsAdds inthstore and floathstore numeric hstore types and helpers pg_numhstore Data types numpgsqlExtensionsExtensionsFunctions and aggregates · ExtensionsArray and numerical computing library for PostgreSQL array math numeric random statistics numpgsql Functions and aggregates numpy_plpython2uExtensionsExtensionsProcedural languages · Extensionstransform between numpy and plpython2u numpy-arrays plpython postgresql-extension numpy_plpython2u Procedural languages numpy_plpython3uExtensionsExtensionsProcedural languages · Extensionstransform between numpy and plpython3u numpy-arrays plpython postgresql-extension numpy_plpython3u Procedural languages numpy_plpythonuExtensionsExtensionsProcedural languages · Extensionstransform between numpy and plpythonu numpy-arrays plpython postgresql-extension numpy_plpythonu Procedural languages nvlfuncExtensionsExtensionsCompatibility · ExtensionsOracle-compatible NVL function compatibility oracle nvlfunc Compatibility oai_fdwExtensionsExtensionsForeign data wrappers · ExtensionsOAI-PMH foreign data wrapper for PostgreSQL fdw metadata oai-pmh oai_fdw Foreign data wrappers OAuth Authorization/AuthenticationManual ChaptersPG18OAuth 2.0 is an industry-standard framework, defined in RFC 6749, to enable third-party applications to obtain limited access to a protected resource. OAuth client support has to be enabled … OAuth SupportManual ChaptersPG18libpq implements support for the OAuth v2 Device Authorization client flow, documented in RFC 8628, as an optional module. See the installation documentation for information on how to enable… OAuth Validator CallbacksManual ChaptersPG18OAuth validator modules implement their functionality by defining a set of callbacks. The server will call them as required to process the authentication request from the user. OAuth Validator ModulesManual ChaptersPG18PostgreSQL provides infrastructure for creating custom modules to perform server-side validation of OAuth bearer tokens. Because OAuth implementations vary so wildly, and bearer token valida… OAUTHBEARER AuthenticationManual ChaptersPG18SASL AuthenticationOAUTHBEARER is a token-based mechanism for federated authentication. It is described in detail in RFC 7628. A typical exchange differs depending on whether or not the client already has a be… Object Identifier TypesManual ChaptersPG18Object identifiers (OIDs) are used internally by PostgreSQL as primary keys for various system tables. Type oid represents an object identifier. There are also several alias types for oid, e… Object Information and Addressing FunctionsManual ChaptersPG18System Information Functions and OperatorsTable 9.81 lists functions related to database object identification and addressing. Table 9.81. Object Information and Addressing Functions Function Description pg_get_acl ( classid oid, ob… Object Name OptionsManual ChaptersPG18postgres_fdw — access data stored in external PostgreSQL serversThese options can be used to control the names used in SQL statements sent to the remote PostgreSQL server. These options are needed when a foreign table is created with names different from… object_referenceExtensionsExtensionsFeatures · ExtensionsProvides immutable references to Postgres objects. object_reference Features oblivpg_fdwExtensionsExtensionsForeign data wrappers · ExtensionsOblivious foreign data wrapper for table access backed by trusted hardware and ORAM fdw oram privacy sgx oblivpg_ftw Foreign data wrappers obs_fdwExtensionsExtensionsForeign data wrappers · ExtensionsHuawei Cloud OBS foreign data wrapper extension listed for RDS PostgreSQL. fdw huawei object-storage obs obs_fdw Foreign data wrappers Obsolete Functions for COPYManual ChaptersPG18Functions Associated with the COPY CommandThese functions represent older methods of handling COPY. Although they still work, they are deprecated due to poor error handling, inconvenient methods of detecting end-of-data, and lack of… Obsolete Functions for Sending Cancel RequestsManual ChaptersPG18Canceling Queries in ProgressThese functions represent older methods of sending cancel requests. Although they still work, they are deprecated due to not sending the cancel requests in an encrypted manner, even when the… Obsolete or Renamed FeaturesManual ChaptersPG18Functionality is sometimes removed from PostgreSQL, feature, setting and file names sometimes change, or documentation moves to different places. This section directs users coming from old v… Obtaining Execution Location InformationManual ChaptersPG18Control StructuresThe GET DIAGNOSTICS command, previously described in Section 41.5.5, retrieves information about current execution state (whereas the GET STACKED DIAGNOSTICS command discussed above reports … Obtaining Information about an ErrorManual ChaptersPG18Control StructuresException handlers frequently need to identify the specific error that occurred. There are two ways to get information about the current exception in PL/pgSQL: special variables and the GET … Obtaining the Result StatusManual ChaptersPG18Basic StatementsThere are several ways to determine the effect of a command. The first method is to use the GET DIAGNOSTICS command, which has the form: GET [ CURRENT ] DIAGNOSTICS variable { = | := } item …