#116 Which DateTime is nil?

Herder-IT-Solutions · Mar 8, 2017 · 9207b8e · 9207b8e
1 parent 75c94c1
commit 9207b8e
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Showing 3 changed files with 38 additions and 22 deletions.
diff --git a/lazarus/DBConnection.pas b/lazarus/DBConnection.pas
@@ -195,7 +195,10 @@ procedure TDBConnection.setStudentFields(var resultVar: ArrayOfStudents;
           FieldByName('first_name').AsString);
         resultVar[length(resultVar) - 1].setClassName(
           FieldByName('class_name').AsString);
-        resultVar[length(resultVar) - 1].setBirth(FieldByName('birth').AsDateTime);
+
+        if not (FieldByName('birth').IsNull) then
+          resultVar[length(resultVar) - 1].setBirth(FieldByName('birth').AsDateTime);
+
         resultVar[length(resultVar) - 1].setLDAPUser(FieldByName('ldap_user').AsString);
         if returnOne then
           exit;
@@ -419,7 +422,12 @@ function TDBConnection.updateInsertStudent(student: TStudent): boolean;
       FieldByName('last_name').AsString := student.getLastName;
       FieldByName('first_name').AsString := student.getFirstName;
       FieldByName('class_name').AsString := student.getClassName;
-      FieldByName('birth').AsDateTime := student.getBirth;
+
+      if student.getBirth <= -1 then //if set to null
+        FieldByName('birth').Clear
+      else
+        FieldByName('birth').AsDateTime := student.getBirth;
+
       FieldByName('ldap_user').AsString := student.getLDAPUser;
       Post; //add to change buffer
       ApplyUpdates; //commit change buffer to db
@@ -481,8 +489,11 @@ procedure TDBConnection.setRentalFields(var resultVar: ArrayOfRentals;
         resultVar[length(resultVar) - 1].setBookId(FieldByName('book_id').AsLargeInt);
         resultVar[length(resultVar) - 1].setStudentId(
           FieldByName('student_id').AsLargeInt);
-        resultVar[length(resultVar) - 1].setReturnDate(
-          FieldByName('return_date').AsDateTime);
+
+        if not (FieldByName('return_date').IsNull) then
+          resultVar[length(resultVar) - 1].setReturnDate(
+            FieldByName('return_date').AsDateTime);
+
         resultVar[length(resultVar) - 1].setRentalDate(
           FieldByName('rental_date').AsDateTime);
         if returnOne then
@@ -578,7 +589,12 @@ function TDBConnection.updateInsertRental(rental: TRental): boolean;
       FieldByName('student_id').AsLargeInt := rental.getStudentId;
       FieldByName('book_id').AsLargeInt := rental.getBookId;
       FieldByName('rental_date').AsDateTime := rental.getRentalDate;
-      FieldByName('return_date').AsDateTime := rental.getReturnDate;
+
+      if rental.getReturnDate <= -1 then //if set to null
+        FieldByName('return_date').Clear
+      else
+        FieldByName('return_date').AsDateTime := rental.getReturnDate;
+
       Post; //add to change buffer
       ApplyUpdates; //commit change buffer to db
       SQLTransaction.commit;

diff --git a/lazarus/rental.pas b/lazarus/rental.pas
@@ -10,38 +10,38 @@ interface
 type
   TRental = class
   private
-    id: LongInt;
-    book_id: LongInt;
-    student_id: LongInt;
+    id: longint;
+    book_id: longint;
+    student_id: longint;
     return_date: TDate;
     rental_date: TDate;
   public
     // Returns the id
     // result: id
-    function getId(): LongInt;
+    function getId(): longint;
 
     // Sets a new id
     // parameter: newId
     // result: TRUE on success, so if newID is not NULL
-    function setId(newId: LongInt): boolean;
+    function setId(newId: longint): boolean;
 
     // Returns the book id
     // result: book_id
-    function getBookId(): LongInt;
+    function getBookId(): longint;
 
     // Sets a new book id
     // parameter: newBookId
     // result: TRUE on success, so if newBookID is not NULL
-    function setBookId(newBookId: LongInt): boolean;
+    function setBookId(newBookId: longint): boolean;
 
     // Returns the student id
     // result: student_id
-    function getStudentId(): LongInt;
+    function getStudentId(): longint;
 
     // Sets a new sudent id
     // parameter: newStudentId
     // result: TRUE on success, so if new StudentId is not NULL
-    function setStudentId(newStudentId: LongInt): boolean;
+    function setStudentId(newStudentId: longint): boolean;
 
     // Returns the book return date
     // result: return_date
@@ -66,12 +66,12 @@   TRental = class
 
 implementation
 
-function TRental.getId(): LongInt;
+function TRental.getId(): longint;
 begin
   Result := self.id;
 end;
 
-function TRental.setId(newId: LongInt): boolean;
+function TRental.setId(newId: longint): boolean;
 begin
   Result := False;
   if (newId <> NULL) then
@@ -81,12 +81,12 @@ function TRental.setId(newId: LongInt): boolean;
   end;
 end;
 
-function TRental.getBookId(): LongInt;
+function TRental.getBookId(): longint;
 begin
   Result := self.book_id;
 end;
 
-function TRental.setBookId(newBookId: LongInt): boolean;
+function TRental.setBookId(newBookId: longint): boolean;
 begin
   Result := False;
   if (newBookId <> NULL) then
@@ -96,12 +96,12 @@ function TRental.setBookId(newBookId: LongInt): boolean;
   end;
 end;
 
-function TRental.getStudentId(): LongInt;
+function TRental.getStudentId(): longint;
 begin
   Result := self.student_id;
 end;
 
-function TRental.setStudentId(newStudentId: LongInt): boolean;
+function TRental.setStudentId(newStudentId: longint): boolean;
 begin
   Result := False;
   if (newStudentId <> NULL) then
@@ -146,7 +146,7 @@ constructor TRental.Create;
   self.id := -1;
   self.book_id := -1;
   self.student_id := -1;
-  self.return_date := -1;
+  self.return_date := -1; // -1 or smaller equals NULL
   self.rental_date := -1;
 end;
 

diff --git a/lazarus/student.pas b/lazarus/student.pas
@@ -172,7 +172,7 @@ constructor TStudent.Create;
   self.last_name := '';
   self.first_name := '';
   self.class_name := '';
-  self.birth := -1;
+  self.birth := -1; // -1 or smaller equals NULL
   self.ldap_user := '';
 end;