-- NutOps.mesa
-- useful database utilities
-- Implemented by: NutOpsImpl
-- Created by: Donahue on: January 20, 1983 3:48 pm
-- last edited by: Donahue, July 12, 1983 9:21 am
-- Last Edited by: Willie-sue, February 22, 1983 3:44 pm
-- Last Edited by: Cattell, July 22, 1983 2:59 pm

DIRECTORY
DB,
ViewerClasses USING[ Viewer ],
Rope USING [ROPE];

NutOps: CEDAR DEFINITIONS =
BEGIN

OPEN DB, Rope;

-- **********************************************
-- Handy DB routines, implemented by NutOpsImpl.mesa
-- **********************************************

IsSystemDomain:PROC[d: Domain] RETURNS[BOOLEAN];

IsSystemRelation: PROC[r: Relation] RETURNS[BOOLEAN];

AttributesOf: PROC[r: Relation] RETURNS[AttributeList];
-- Returns list of r's attributes

FirstAttributeOf: PROC[r: Relation] RETURNS[Attribute];
-- returns AttributesOf[r].first

EntityValued: PROC [a: Attribute] RETURNS[BOOL];
-- returns TRUE iff the value stored in attribute a should be an entity

GetUniquenessString: PROC[a: Attribute] RETURNS[ROPE];
-- returns the uniqueness of a: Key, OptionalKey, etc., as a printable string

RSetSize: PROC[rs: RelshipSet] RETURNS[INT];
-- returns the length of rs, and does a ReleaseRelshipSet

GetTuples: PROC[e: Entity, a: Attribute] RETURNS [tl: LIST OF Relship];
-- returns all the tuples that reference e via attribute a

GetRelation: PROC[a: Attribute] RETURNS[r: Relation];
-- finds a's relation

GetRefAttributes: PROC[d: Domain] RETURNS[al: LIST OF Attribute];
-- returns all the attributes that can reference an entity from domain d

RemoveAttribute: PROC[a: Attribute, al: AttributeList] RETURNS[AttributeList];
-- destructively removes a from al

AppendAttributes: PROC [al1, al2: AttributeList] RETURNS [al: AttributeList];
-- destructively appends al1 and al2 and returns the result

-- ***********************************************
-- Opening segments and transactions for them
-- ***********************************************

SetUpSegment: PROC[
segmentFile: ROPE, seg: DB.Segment, number: NAT← 0, makeReadOnly: BOOL← FALSE ]
RETURNS [success: BOOL, readOnly: BOOL];

Do: PROC[
proc: PROC[ REF ANY ], clientData: REF ANY ← NIL,
reTry: BOOL ← FALSE, msgViewer: ViewerClasses.Viewer ← NIL ]
RETURNS [succeeded: BOOL];
-- Evaluates the procedure supplied in an environment where the Aborted and Failed signals
-- that may be raised from DB will be caught; the procedure will be retried after a restart
-- if reTry is TRUE (otherwise a restart will be performed on failure without retrying the proc.
-- Any messages produced will be printed in the msgViewer if one is supplied.
-- We return succeeded=TRUE iff no errors occured in executing proc.

TryRestart: PROC[trans: DB.Transaction];
-- Attempts to re-open an aborted transaction if user confirms.

AtomFromSegment: PROC[ segR: ROPE ] RETURNS[ ATOM ];

IsLocalName: PROC[ segR: ROPE ] RETURNS[ BOOL ];

END.