1- What is a foreign key constraint- Why are such constraints importan.pdf

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1. What is a foreign key constraint? Why are such constraints important? What is referential integrity? (10 pts) 2. Explain the difference between external, internal, and conceptual schemas. How are these different schema layers related to the concepts of logical and physical data independence? (10 pts).

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1. The design of a singly-linked list below is a picture of the function that needs to be used below is the code of the above picture: #include <string> #include <iostream> #include <cmath> #include <cstdio> #include <algorithm> using namespace std; #define defaultSize 100 void Assert(bool val, string s) { if (!val) { // Assertion failed -- close the program cout << "Assertion Failed: " << s << endl; exit(-1); } } template <typename E> class Link { public: E element; // Value for this node Link *next; // Pointer to next node in list // Constructors Link(const E& elemval, Link<E>* nextval = NULL) { element = elemval; next = nextval; } Link(Link<E>* nextval =NULL) { next = nextval; } }; template <typename E> class LList: public Link<E> { private: Link<E>* head;// Intialization helper method Link<E>* tail;// Pointer to last element Link<E>* curr;// Access to current element int cnt;// Size of list void init(){// Intialization helper method curr = tail = head = new Link<E>; cnt = 0; } void removeall() {// Return link nodes to free store while(head != NULL) { curr = head; head = head->next; delete curr; } } public: LList(int size=defaultSize) { init(); }// Constructor ~LList() { removeall(); }// Destructor void print() const;// Print list contents void clear() { removeall(); init(); }// Clear list // Insert "it" at current position void insert(const E& it) { curr->next = new Link<E>(it, curr->next); if (tail == curr) tail = curr->next; // New tail cnt++; } void append(const E& it) { // Append "it" to list tail = tail->next = new Link<E>(it, NULL); cnt++; } // Remove and return current element E remove() { Assert(curr->next != NULL, "No element"); E it = curr->next->element; // Remember value Link<E>* ltemp = curr->next; // Remember link node if (tail == curr->next) tail = curr; // Reset tail curr->next = curr->next->next; // Remove from list delete ltemp; // Reclaim space cnt--; // Decrement the count return it; } void moveToStart()// Place curr at list start { curr = head; } void moveToEnd() // Place curr at list end { curr = tail; } void prev(){ if (curr == head) return; Link<E>* temp = head; while (temp->next!=curr) temp=temp->next; curr = temp; } void next(){ if (curr != tail) curr = curr->next; } int length() const { return cnt; } int currPos() const { Link<E>* temp = head; int i; for (i=0; curr != temp; i++) temp = temp->next; return i; } void moveToPos(int pos){ Assert ((pos>=0)&&(pos<=cnt), "Position out of range"); curr = head; for(int i=0; i<pos; i++) curr = curr->next; } const E& getValue() const { Assert(curr->next != NULL, "No value"); return curr->next->element; } }; completed this code to fulfill the requirement below: Write a function to insert an integer into a singly-linked list of elements arranged from largest to smallest. Requires that elements remain ordered after insertion. 2. The design of array-based stack below is a picture of the function that needs to be used below is the code of the above picture: #include <string.h> #.

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1- What is a foreign key constraint- Why are such constraints importan.pdf

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1- What is a foreign key constraint- Why are such constraints importan.pdf