Package org.apache.derby.iapi.sql.conn

Interface SQLSessionContext

  • All Known Implementing Classes:
    SQLSessionContextImpl
    public interface SQLSessionContext
    An implementation of this interface encapsulates some of the SQL session context's state variables, cf. SQL 2003, section 4.37.3, notably those which we need to save and restore when entering a stored procedure or function (which can contain SQL and thus a nested connection), cf. 4.37.3, 4.27.3 and 4.34.1.1.

    Presently this set contains the following properties:

    • current role
    • current schema
    The standard specifies that the authorization stack be copied onto the new SQL session context before it is pushed (and possibly modifed) with a new cell for the authorization ids (user, role). In our implementation we merge these two stacks for now. Also, the authorization id of current user is not represented yet, since it can not be modified in a session; Derby can not run routines with definer's rights yet.

    SQL session context is implemented as follows: Statements at root connection level use the instance held by the the lcc, nested connections maintain instances of SQLSessionContext, held by the activation of the calling statement. This forms a logical stack as required by the standard. The statement context also holds a reference to the current SQLSessionContext.

    When a dynamic result set references e.g. current role, the value retrieved will always be that of the current role when the statement is logically executed (inside procedure/function), not the current value when the result set is accessed outside the stored procedure/function. This works since the nested SQL session context is kept by the caller activation, so even though the statement context of the call has been popped, we can get at the final state of the nested SQL session context since the caller's activation is alive as long as dynamic result sets need it).

    If more than one nested connection is used inside a shared procedure, they will share the same nested SQL session context. Since the same dynamic call context is involved, this seems correct.

    See Also:
    LanguageConnectionContext.pushNestedSessionContext(org.apache.derby.iapi.sql.Activation, boolean, java.lang.String)

    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      java.util.HashMap<UUID,​java.lang.Boolean> getConstraintModes()
      Get a handle to the session's constraint modes.
      java.lang.String getCurrentUser()
      Get the SQL current user of this SQL connection context
      SchemaDescriptor getDefaultSchema()
      Get the schema of this SQL connection context
      java.lang.Boolean getDeferredAll()
      Get state of DEFERRED ALL setting.
      java.lang.String getRole()
      Get the SQL role of this SQL connection context
      java.lang.Boolean isDeferred​(UUID constraintId)
      Return Boolean.TRUE if the constraint mode for this constraint/index has been set to deferred, Boolean.FALSE if it has been set to immediate.
      void resetConstraintModes()
      Clear deferred information for this transaction.
      void setConstraintModes​(java.util.HashMap<UUID,​java.lang.Boolean> hm)
      Initialize a inferior session context with the constraint mode map of the parent session context.
      void setDefaultSchema​(SchemaDescriptor sd)
      Set the schema of this SQL connection context
      void setDeferred​(UUID constraintId, boolean deferred)
      Set the constraint mode for this constraint to deferred.
      void setDeferredAll​(java.lang.Boolean deferred)
      Set the constraint mode for all deferrable constraints to deferred.
      void setRole​(java.lang.String role)
      Set the SQL role of this SQL connection context
      void setUser​(java.lang.String user)
      Set the SQL current user of this SQL connection context

    • Method Detail

      • setRole

        void setRole​(java.lang.String role)
        Set the SQL role of this SQL connection context

      • getRole

        java.lang.String getRole()
        Get the SQL role of this SQL connection context

      • setUser

        void setUser​(java.lang.String user)
        Set the SQL current user of this SQL connection context

      • getCurrentUser

        java.lang.String getCurrentUser()
        Get the SQL current user of this SQL connection context

      • setDefaultSchema

        void setDefaultSchema​(SchemaDescriptor sd)
        Set the schema of this SQL connection context

      • getDefaultSchema

        SchemaDescriptor getDefaultSchema()
        Get the schema of this SQL connection context

      • getConstraintModes

        java.util.HashMap<UUID,​java.lang.Boolean> getConstraintModes()
        Get a handle to the session's constraint modes. The caller is responsible for any cloning needed.
        Returns:
        constraint modes map

      • setConstraintModes

        void setConstraintModes​(java.util.HashMap<UUID,​java.lang.Boolean> hm)
        Initialize a inferior session context with the constraint mode map of the parent session context.
        Parameters:
        hm - constraint mode map

      • setDeferred

        void setDeferred​(UUID constraintId,
                 boolean deferred)
        Set the constraint mode for this constraint to deferred. If deferred is false, to immediate checking, if true to deferred checking.
        Parameters:
        constraintId - The constraint id
        deferred - The new constraint mode

      • isDeferred

        java.lang.Boolean isDeferred​(UUID constraintId)
        Return Boolean.TRUE if the constraint mode for this constraint/index has been set to deferred, Boolean.FALSE if it has been set to immediate. Any ALL setting is considered also. If the constraint mode hasn't been set for this constraint, return null. The constraint mode is the effectively the initial constraint mode in this case.
        Parameters:
        constraintId - the constraint id
        Returns:
        Boolean.TRUE if the constraint mode for this constraint/index has been set to deferred, Boolean.FALSE if it has been set to immediate.

      • resetConstraintModes

        void resetConstraintModes()
        Clear deferred information for this transaction.

      • setDeferredAll

        void setDeferredAll​(java.lang.Boolean deferred)
        Set the constraint mode for all deferrable constraints to deferred. If deferred is false, set to immediate checking, if true to deferred checking. null is allowed: it means no ALL setting exists.
        Parameters:
        deferred - the mode to set

      • getDeferredAll

        java.lang.Boolean getDeferredAll()
        Get state of DEFERRED ALL setting.
        Returns:
        True is deferred all constraint mode has been set for this session context. False is deferred immediate has been set for this session context. null means no ALL setting has been made for this context