1 / 31

Oracle C++ Call Interface

Oracle C++ Call Interface. Dirk Geppert IT/DB DB Workshop July 11-13, 2001. Outline. Overview Advanced features Example Summary Advanced example. What is it?. API to access Oracle database OCI Oracle Call Interface OCCI Oracle C++ Call Interface OCCI a better OCI: wrapper

vidar
Download Presentation

Oracle C++ Call Interface

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Oracle C++ Call Interface Dirk Geppert IT/DB DB Workshop July 11-13, 2001

  2. Outline • Overview • Advanced features • Example • Summary • Advanced example

  3. What is it? • API to access Oracle database • OCI Oracle Call Interface • OCCI Oracle C++ Call Interface • OCCI a better OCI: wrapper • scalable, high performance, multi-tiered • ANSI C++, STL • JDBC like

  4. What to use it for? • Relational Programming • Associative Access of Relational Data • SQL DDL (data definition) • SQL DML (data manipulating) • SQL queries • PL/SQL • Object Programming • Navigational andAssociative Access of Objects

  5. Advanced features • Thread safety • Connection pooling • Client-side object cache • Complex Object Retrieval • Metadata • Context USER

  6. Thread safety • Oracle database server and OCCI in multi-threaded environment • Mechanism to maintain integrity of data accessed by multiple threads • Mutexes are granted on basis of OCCI Environment class • THREADED_MUTEXED • Thread safe, mutexed internally managed by OCCI • THREADED_UN_MUTEXED • Thread safe, client responsible for mutexing

  7. Connection pooling • Multi-threading typically • large number of threads need connections to DB for short duration • Open connection for each thread • Inefficient • Poor performance • OCCI connection pooling • create small number of connections • dynamically select free connectionto execute statement • release connection

  8. Client-side object cache • Memory buffer for objects • Lookup and memory management support • Stores and tracks objects fetched from server to client side • Maintains references • Manages automatic object swapping • Meta-attributes or type information • Created when OCCI-Environment initialized in object mode • Benefits • Reduces client/server round-trips • Object-level locking

  9. Complex Object Retrieval • OO data models • Interrelated objects forming graphs • Navigate/traverse:fetch & pin each object individually • Costly network round-trips (client/server) • Oracle’s Complex Object Retrieval • Pre-fetching (content, boundary) • Specific type up to depth level • All attribute types up to depth level • Objects only pre-fetched, not pinned • Limited by client-side cache size

  10. Metadata • Dynamically discover attributes of database objects • Database itself • Schema objectse.g. tables, columns, types, type attributes,result attributes MetaData evt_md=conn->getMetaData(“Event”); vector<MetaData> attr_list = evt_md.getVector(ATTR_LIST_TYPE_ATTRS);

  11. Context USER • user owns • e.g. tables, types, objects • May grant privileges to other users, roles (named groups of privileges) • Access, modify OCCI_STD_NAMESPACE::string Event_C::getSQLTypeName() const {return OCCI_STD_NAMESPACE::string(“SCOTT.EVENT_C");}

  12. Type mapping • Oracle database - C++ (host language) • Oracle internal – external • Data conversion of C++ data send/requested to/from database

  13. SQL – OTT – C++ PObject ctype Number n Vector< Number > a Ref< mytype > p mytype see Peter’s talk create type array as varray(1000) of number / create type atype as object ( n number, a array, p ref atype) / create table atable of atype; insert into atable values (atype(0,null,null)); commit; type atype generate ctype as mytype SQL OTT OCCI

  14. Generated C++ classes class ctype : public oracle::occi::Pobject { private: // attributes … public: // set & get attributes … void *operator new(size_t size); void *operator new(size_t size, const oracle::occi::Connection * sess, const OCCI_STD_NAMESPACE::string& table); OCCI_STD_NAMESPACE::string getSQLTypeName() const; ctype(); ctype(void *ctxOCCI_) : oracle::occi::PObject (ctxOCCI_) { }; static void *readSQL(void *ctxOCCI_); virtual void readSQL(oracle::occi::AnyData& streamOCCI_); static void writeSQL(void *objOCCI_, void *ctxOCCI_); virtual void writeSQL(oracle::occi::AnyData& streamOCCI_); } Persistent Object transient persistent SQL

  15. Example Session easy to use Environment *env=Environment::createEnvironment(Environment::OBJECT); RegisterMappings(env); Connection *conn=env->createConnection(“scott”,”tiger”,””); Statement *stmt=conn->createStatement(); ResultSet *resultSet=stmt->executeQuery(“select ref(t) from atable t where n=0”); if (ResultSet::DATA_AVAILABLE == resultSet->next()) { Ref<mytype> ref=resultSet->getRef(1); } conn->commit(); stmt->closeResultSet(resultSet); conn->terminateConnection(conn); Environment::terminateEnvironment(env); create/modify/delete objects

  16. Creating new objects Ref<mytype> ref=resultSet->getRef(1); ref_next=new(conn,”ATABLE”) mytype(); ref->setP(ref_next); // forward ref->markModified(); modify persistent Example navigation Ref<mytype> ref=resultSet->getRef(1); do { ref->dump(); mytype *ptr=ref.ptr(); // if needed } while (!((ref=ref->getP()).isNull())); reference dereference, pin pointer

  17. Summary • OCCI is C++ API to communicate with Oracle database server • Built on top of OCI • High-performance • scalable • Easy to use • Does it provide the flexibility to use it for HEP data models & access patterns?Tests are on the way…

  18. Event 1 1 * 1 PObject PObject Header PObject PObject 1 Vertex 1 * Track 1 UML

  19. SQL create type header_o as object (run number,evt number); create type track_o; -- dummy create type track_ref_varray_o as varray(100) of ref track_o; create type vertex_o as object (id number,x number,y number,z number,trk track_ref_varray_o); create type vertex_ref_varray_o as varray(100) of ref vertex_o; create or replace type track_o as object ( id number,px number,py number,pz number,vtx ref vertex_o); create type event_o as object (id number,hdr header,vtx vertex_ref_varray_o,nxt ref event_o); create table event_t of event_o create table vertex_t of vertex_o create table track_t of track_o insert into event_t values (event_o(0,header_o(0,0),null,null)); commit;

  20. OTT TYPE Header_O GENERATE Header_C AS Header TYPE Track_O GENERATE Track_C AS Track TYPE Vertex_O GENERATE Vertex_C AS Vertex TYPE Event_O GENERATE Event_C AS Event User(inherit from C++ class) Oracle C++

  21. C++.h class Event_C : public oracle::occi::PObject { private: oracle::occi::Number ID; Header * HDR; OCCI_STD_NAMESPACE::vector< oracle::occi::Ref< Vertex > > VTX; oracle::occi::Ref< Event > NXT; public: oracle::occi::Number getId() const; void setId(const oracle::occi::Number &value); Header *getHdr() const; void setHdr(Header *value); OCCI_STD_NAMESPACE::vector< oracle::occi::Ref< Vertex > > getVtx() const; void setVtx(const OCCI_STD_NAMESPACE::vector< oracle::occi::Ref< Vertex > > &value); oracle::occi::Ref< Event > getNxt() const; void setNxt(const oracle::occi::Ref< Event > &value); attributes set & get

  22. C++.hcont’d void *operator new(size_t size); void *operator new(size_t size, const oracle::occi::Connection * sess, const OCCI_STD_NAMESPACE::string& table); OCCI_STD_NAMESPACE::string getSQLTypeName() const; Event_C(); Event_C(void *ctxOCCI_) : oracle::occi::PObject (ctxOCCI_) { }; static void *readSQL(void *ctxOCCI_); virtual void readSQL(oracle::occi::AnyData& streamOCCI_); static void writeSQL(void *objOCCI_, void *ctxOCCI_); virtual void writeSQL(oracle::occi::AnyData& streamOCCI_); } ctor new SQL

  23. C++.cpp oracle::occi::Number Event_C::getId() const { return ID; } void Event_C::setId(const oracle::occi::Number &value) { ID = value; } Header_C * Event_c::getHdr() const { return HDR; } void Event_C::setHdr(Header * value) { HDR = value; } OCCI_STD_NAMESPACE::vector< oracle::occi::Ref< Vertex > > Event_C::getVtx() const { return VTX; } void Event_C::setVtx(const OCCI_STD_NAMESPACE::vector<oracle::occi::Ref<Vertex>> &value) { VTX = value; } oracle::occi::Ref< Event > Event_C::getNxt() const { return NXT; } void Event_C::setNxt(const oracle::occi::Ref< Event > &value) { NXT = value; } set & get

  24. C++.cppcont’d void *Event_C::operator new(size_t size) { return oracle::occi::PObject::operator new(size); } void *Event_C::operator new(size_t size, const oracle::occi::Connection * sess, const OCCI_STD_NAMESPACE::string& table) { return oracle::occi::PObject::operator new(size, sess, table, (char *) “SCOTT.EVENT_O"); } OCCI_STD_NAMESPACE::string Event_C::getSQLTypeName() const { return OCCI_STD_NAMESPACE::string(“SCOTT.EVENT_O"); } Event_C::Event_C() {HDR = (Header *) 0;} new ctor

  25. C++.cppcont’d void *Event_C::readSQL(void *ctxOCCI_) { Event_C *objOCCI_ = new Event_C(ctxOCCI_); oracle::occi::AnyData streamOCCI_(ctxOCCI_); try { if (streamOCCI_.isNull()) objOCCI_->setNull(); else objOCCI_->readSQL(streamOCCI_); } catch (oracle::occi::SQLException& excep) { delete objOCCI_; excep.setErrorCtx(ctxOCCI_); return (void *)NULL; } return (void *)objOCCI_; } void Event_C::readSQL(oracle::occi::AnyData& streamOCCI_) { ID = streamOCCI_.getNumber(); HDR = (Header *) streamOCCI_.getObject(); getVector(streamOCCI_, VTX); NXT = streamOCCI_.getRef(); } readSQL

  26. C++.cppcont’d void Event_C::writeSQL(void *objectOCCI_, void *ctxOCCI_) { Event_C *objOCCI_ = (Event_C *) objectOCCI_; oracle::occi::AnyData streamOCCI_(ctxOCCI_); try { if (objOCCI_->isNull()) streamOCCI_.setNull(); else objOCCI_->writeSQL(streamOCCI_); } catch (oracle::occi::SQLException& excep) { excep.setErrorCtx(ctxOCCI_); } return; } void Event_C::writeSQL(oracle::occi::AnyData& streamOCCI_) { streamOCCI_.setNumber(ID); streamOCCI_.setObject(HDR); setVector(streamOCCI_,VTX); streamOCCI_.setRef(NXT); } writeSQL

  27. User C++ class Event : public Event_C { public: void dump(); }; void Event::dump() { cout << "Event::dump()" << endl; cout << " ID= " << int(getId()) << endl; if (getHdr()!=0) getHdr()->dump(); OCCI_STD_NAMESPACE::vector< oracle::occi::Ref< Vertex > > &vtx=getVtx(); cout << " Vtx length= " << vtx.size() << endl; for (int i=0; i<vtx.size(); i++) { oracle::occi::Ref< Vertex > v=vtx[i]; v->dump(); } if (getNxt().isNull()) cout << " Next is NULL" << endl; else cout << " Next exists " << endl; };

  28. Navigation - write Ref<Event> evt_ref, evt_ref_next; Event *evt_ptr, *evt_ptr_next; unsigned long int eid,vid,tid; int evt,run; Header* hdr; Vertex* vtx; Track* trk; evt_ref = resultSet->getRef(1); for (int ievent=0; ievent<nevent; ievent++) { hdr = new Header(); // and set attributes… Header

  29. Navigation - writecont’d OCCI_STD_NAMESPACE::vector< oracle::occi::Ref< Vertex > > vtx_ref_arr; for (int ivertex=0; ivertex<nvertex; ivertex++) { vtx=new (conn,"VERTEX_T") Vertex(); OCCI_STD_NAMESPACE::vector< oracle::occi::Ref< Track > > trk_ref_arr; for (int itrack=0; itrack<2; itrack++) { trk=new (conn,"TRACK_T") Track(); trk->setVtx(vtx); // and other attributes… trk_ref_arr.push_back(trk); } vtx->setTrk(trk_ref_arr); // and other attributes… vtx_ref_arr.push_back(vtx); } evt_ptr_next = new(conn,"EVENT_T") Event(); evt_ptr_next->setHdr(hdr); evt_ptr_next->setVtx(vtx_ref_arr); // and other attributes… evt_ptr->setNxt(evt_ptr_next); // forward pointing evt_ptr->markModified(); conn->commit(); evt_ptr=evt_ptr_next; } Vertex Track Event

  30. Navigation - read Ref<Myevent> evt_ref = resultSet->getRef(1); do { evt_ref->dump(); } while (!((evt_ref=evt_ref->getNxt()).isNull()));

  31. Object Type Translator SQL DDL INTYPE file OTT Type Definitions MAPFILE file CPPFILE file HFILE file Database Server OCCI Source Compiler OCCI library Linker Object file Executable 2 1 3 4 5

More Related