Package org.postgresql

Interface PGConnection

  • All Known Subinterfaces:
    BaseConnection
    All Known Implementing Classes:
    PgConnection
    public interface PGConnection
    This interface defines the public PostgreSQL extensions to java.sql.Connection. All Connections returned by the PostgreSQL driver implement PGConnection.

    • Method Summary

      All Methods Instance Methods Abstract Methods Deprecated Methods 
      Modifier and Type Method Description
      void addDataType​(java.lang.String type, java.lang.Class<? extends PGobject> klass)
      This allows client code to add a handler for one of org.postgresql's more unique data types.
      void addDataType​(java.lang.String type, java.lang.String className)
      Deprecated.
      As of 8.0, replaced by addDataType(String, Class).
      void cancelQuery()
      Sends a query cancellation for this connection.
      java.sql.Array createArrayOf​(java.lang.String typeName, java.lang.Object elements)
      Creates an Array wrapping elements.
      java.lang.String escapeIdentifier​(java.lang.String identifier)
      Return the given string suitably quoted to be used as an identifier in an SQL statement string.
      java.lang.String escapeLiteral​(java.lang.String literal)
      Return the given string suitably quoted to be used as a string literal in an SQL statement string.
      AutoSave getAutosave()
      Connection configuration regarding automatic per-query savepoints.
      int getBackendPID()
      Return the process ID (PID) of the backend server process handling this connection.
      CopyManager getCopyAPI()
      This returns the COPY API for the current connection.
      int getDefaultFetchSize()
      Get the default fetch size for statements created from this connection.
      Fastpath getFastpathAPI()
      Deprecated.
      This API is somewhat obsolete, as one may achieve similar performance and greater functionality by setting up a prepared statement to define the function call.
      LargeObjectManager getLargeObjectAPI()
      This returns the LargeObject API for the current connection.
      PGNotification[] getNotifications()
      This method returns any notifications that have been received since the last call to this method.
      PGNotification[] getNotifications​(int timeoutMillis)
      This method returns any notifications that have been received since the last call to this method.
      java.lang.String getParameterStatus​(java.lang.String parameterName)
      Shorthand for getParameterStatuses().get(...) .
      java.util.Map<java.lang.String,​java.lang.String> getParameterStatuses()
      Returns the current values of all parameters reported by the server.
      PreferQueryMode getPreferQueryMode()
      Returns the query mode for this connection.
      int getPrepareThreshold()
      Get the default server-side prepare reuse threshold for statements created from this connection.
      PGReplicationConnection getReplicationAPI()  
      void setAutosave​(AutoSave autoSave)
      Configures if connection should use automatic savepoints.
      void setDefaultFetchSize​(int fetchSize)
      Set the default fetch size for statements created from this connection.
      void setPrepareThreshold​(int threshold)
      Set the default statement reuse threshold before enabling server-side prepare.

    • Method Detail

      • createArrayOf

        java.sql.Array createArrayOf​(java.lang.String typeName,
                             java.lang.Object elements)
                      throws java.sql.SQLException
        Creates an Array wrapping elements. This is similar to Connection.createArrayOf(String, Object[]), but also provides support for primitive arrays.
        Parameters:
        typeName - The SQL name of the type to map the elements to. Must not be null.
        elements - The array of objects to map. A null value will result in an Array representing null.
        Returns:
        An Array wrapping elements.
        Throws:
        java.sql.SQLException - If for some reason the array cannot be created.
        See Also:
        Connection.createArrayOf(String, Object[])

      • getNotifications

        PGNotification[] getNotifications()
                           throws java.sql.SQLException
        This method returns any notifications that have been received since the last call to this method. Returns null if there have been no notifications.
        Returns:
        notifications that have been received
        Throws:
        java.sql.SQLException - if something wrong happens
        Since:
        7.3

      • getNotifications

        PGNotification[] getNotifications​(int timeoutMillis)
                           throws java.sql.SQLException
        This method returns any notifications that have been received since the last call to this method. Returns null if there have been no notifications. A timeout can be specified so the driver waits for notifications.
        Parameters:
        timeoutMillis - when 0, blocks forever. when > 0, blocks up to the specified number of millies or until at least one notification has been received. If more than one notification is about to be received, these will be returned in one batch.
        Returns:
        notifications that have been received
        Throws:
        java.sql.SQLException - if something wrong happens
        Since:
        43

      • getCopyAPI

        CopyManager getCopyAPI()
                throws java.sql.SQLException
        This returns the COPY API for the current connection.
        Returns:
        COPY API for the current connection
        Throws:
        java.sql.SQLException - if something wrong happens
        Since:
        8.4

      • getLargeObjectAPI

        LargeObjectManager getLargeObjectAPI()
                              throws java.sql.SQLException
        This returns the LargeObject API for the current connection.
        Returns:
        LargeObject API for the current connection
        Throws:
        java.sql.SQLException - if something wrong happens
        Since:
        7.3

      • getFastpathAPI

        @Deprecated
Fastpath getFastpathAPI()
                 throws java.sql.SQLException
        Deprecated.
        This API is somewhat obsolete, as one may achieve similar performance and greater functionality by setting up a prepared statement to define the function call. Then, executing the statement with binary transmission of parameters and results substitutes for a fast-path function call.
        This returns the Fastpath API for the current connection.
        Returns:
        Fastpath API for the current connection
        Throws:
        java.sql.SQLException - if something wrong happens
        Since:
        7.3

      • addDataType

        @Deprecated
void addDataType​(java.lang.String type,
                 java.lang.String className)
        Deprecated.
        As of 8.0, replaced by addDataType(String, Class). This deprecated method does not work correctly for registering classes that cannot be directly loaded by the JDBC driver's classloader.
        This allows client code to add a handler for one of org.postgresql's more unique data types. It is approximately equivalent to addDataType(type, Class.forName(name)).
        Parameters:
        type - JDBC type name
        className - class name
        Throws:
        java.lang.RuntimeException - if the type cannot be registered (class not found, etc).

      • addDataType

        void addDataType​(java.lang.String type,
                 java.lang.Class<? extends PGobject> klass)
          throws java.sql.SQLException

        This allows client code to add a handler for one of org.postgresql's more unique data types.

        NOTE: This is not part of JDBC, but an extension.

        The best way to use this is as follows:

         ...
 ((org.postgresql.PGConnection)myconn).addDataType("mytype", my.class.name.class);
 ...

        where myconn is an open Connection to org.postgresql.

        The handling class must extend org.postgresql.util.PGobject

        Parameters:
        type - the PostgreSQL type to register
        klass - the class implementing the Java representation of the type; this class must implement PGobject).
        Throws:
        java.sql.SQLException - if klass does not implement PGobject).
        Since:
        8.0
        See Also:
        PGobject

      • setPrepareThreshold

        void setPrepareThreshold​(int threshold)
        Set the default statement reuse threshold before enabling server-side prepare. See PGStatement.setPrepareThreshold(int) for details.
        Parameters:
        threshold - the new threshold
        Since:
        build 302

      • getPrepareThreshold

        int getPrepareThreshold()
        Get the default server-side prepare reuse threshold for statements created from this connection.
        Returns:
        the current threshold
        Since:
        build 302

      • setDefaultFetchSize

        void setDefaultFetchSize​(int fetchSize)
                  throws java.sql.SQLException
        Set the default fetch size for statements created from this connection.
        Parameters:
        fetchSize - new default fetch size
        Throws:
        java.sql.SQLException - if specified negative fetchSize parameter
        See Also:
        Statement.setFetchSize(int)

      • getDefaultFetchSize

        int getDefaultFetchSize()
        Get the default fetch size for statements created from this connection.
        Returns:
        current state for default fetch size
        See Also:
        PGProperty.DEFAULT_ROW_FETCH_SIZE, Statement.getFetchSize()

      • getBackendPID

        int getBackendPID()
        Return the process ID (PID) of the backend server process handling this connection.
        Returns:
        PID of backend server process.

      • cancelQuery

        void cancelQuery()
          throws java.sql.SQLException
        Sends a query cancellation for this connection.
        Throws:
        java.sql.SQLException - if there are problems cancelling the query

      • escapeIdentifier

        java.lang.String escapeIdentifier​(java.lang.String identifier)
                           throws java.sql.SQLException
        Return the given string suitably quoted to be used as an identifier in an SQL statement string. Quotes are added only if necessary (i.e., if the string contains non-identifier characters or would be case-folded). Embedded quotes are properly doubled.
        Parameters:
        identifier - input identifier
        Returns:
        the escaped identifier
        Throws:
        java.sql.SQLException - if something goes wrong

      • escapeLiteral

        java.lang.String escapeLiteral​(java.lang.String literal)
                        throws java.sql.SQLException
        Return the given string suitably quoted to be used as a string literal in an SQL statement string. Embedded single-quotes and backslashes are properly doubled. Note that quote_literal returns null on null input.
        Parameters:
        literal - input literal
        Returns:
        the quoted literal
        Throws:
        java.sql.SQLException - if something goes wrong

      • getPreferQueryMode

        PreferQueryMode getPreferQueryMode()

        Returns the query mode for this connection.

        When running in simple query mode, certain features are not available: callable statements, partial result set fetch, bytea type, etc.

        The list of supported features is subject to change.

        Returns:
        the preferred query mode
        See Also:
        PreferQueryMode

      • getAutosave

        AutoSave getAutosave()
        Connection configuration regarding automatic per-query savepoints.
        Returns:
        connection configuration regarding automatic per-query savepoints
        See Also:
        PGProperty.AUTOSAVE

      • setAutosave

        void setAutosave​(AutoSave autoSave)
        Configures if connection should use automatic savepoints.
        Parameters:
        autoSave - connection configuration regarding automatic per-query savepoints
        See Also:
        PGProperty.AUTOSAVE

      • getReplicationAPI

        PGReplicationConnection getReplicationAPI()
        Returns:
        replication API for the current connection

      • getParameterStatuses

        java.util.Map<java.lang.String,​java.lang.String> getParameterStatuses()

        Returns the current values of all parameters reported by the server.

        PostgreSQL reports values for a subset of parameters (GUCs) to the client at connect-time, then sends update messages whenever the values change during a session. PgJDBC records the latest values and exposes it to client applications via getParameterStatuses().

        PgJDBC exposes individual accessors for some of these parameters as listed below. They are more backwarrds-compatible and should be preferred where possible.

        Not all parameters are reported, only those marked GUC_REPORT in the source code. The pg_settings view does not expose information about which parameters are reportable. PgJDBC's map will only contain the parameters the server reports values for, so you cannot use this method as a substitute for running a SHOW paramname; or SELECT current_setting('paramname'); query for arbitrary parameters.

        Parameter names are case-insensitive and case-preserving in this map, like in PostgreSQL itself. So DateStyle and datestyle are the same key.

        As of PostgreSQL 11 the reportable parameter list, and related PgJDBC interfaces or accesors, are:

        • application_name - Connection.getClientInfo(), Connection.setClientInfo(java.util.Properties) and ApplicationName connection property.
        • client_encoding - PgJDBC always sets this to UTF8. See allowEncodingChanges connection property.
        • DateStyle - PgJDBC requires this to always be set to ISO
        • standard_conforming_strings - indirectly via escapeLiteral(String)
        • TimeZone - set from JDK timezone see TimeZone.getDefault() and TimeZone.setDefault(TimeZone)
        • integer_datetimes
        • IntervalStyle
        • server_encoding
        • server_version
        • is_superuser
        • session_authorization

        Note that some PgJDBC operations will change server parameters automatically.

        Returns:
        unmodifiable map of case-insensitive parameter names to parameter values
        Since:
        42.2.6

      • getParameterStatus

        java.lang.String getParameterStatus​(java.lang.String parameterName)
        Shorthand for getParameterStatuses().get(...) .
        Parameters:
        parameterName - case-insensitive parameter name
        Returns:
        parameter value if defined, or null if no parameter known
        Since:
        42.2.6
        See Also:
        getParameterStatuses()