Support deleting table constraints in Edit Table dialog

This adds support for deleting table constraints in the Edit Table
dialog.

src/EditTableDialog.cpp

@@ -30,9 +30,8 @@ EditTableDialog::EditTableDialog(DBBrowserDB& db, const sqlb::ObjectIdentifier&
     connect(ui->treeWidget, &QTreeWidget::itemChanged, this, &EditTableDialog::fieldItemChanged);
     connect(ui->tableConstraints, &QTableWidget::itemChanged, this, &EditTableDialog::constraintItemChanged);
 
-    // TODO Remove this once we have added support for these buttons
+    // TODO Remove this once we have added support for this button
     ui->buttonAddConstraint->setVisible(false);
-    ui->buttonRemoveConstraint->setVisible(false);
 
     // Set item delegate for foreign key column
     m_fkEditorDelegate = new ForeignKeyEditorDelegate(db, m_table, this);
@@ -69,6 +68,12 @@ EditTableDialog::EditTableDialog(DBBrowserDB& db, const sqlb::ObjectIdentifier&
         ui->labelEditWarning->setVisible(false);
     }
 
+    // Enable/disable remove constraint button depending on whether a constraint is selected
+    connect(ui->tableConstraints, &QTableWidget::itemSelectionChanged, [this]() {
+        bool hasSelection = ui->tableConstraints->selectionModel()->hasSelection();
+        ui->buttonRemoveConstraint->setEnabled(hasSelection);
+    });
+
     // And create a savepoint
     pdb.setSavepoint(m_sRestorePointName);
 
@@ -818,3 +823,23 @@ void EditTableDialog::changeSchema(const QString& /*schema*/)
     // Update the SQL preview
     updateSqlText();
 }
+
+void EditTableDialog::removeConstraint()
+{
+    // Is there any item selected to delete?
+    if(!ui->tableConstraints->currentItem())
+        return;
+
+    // Find constraint to delete
+    int row = ui->tableConstraints->currentRow();
+    sqlb::StringVector columns = ui->tableConstraints->item(row, kConstraintColumns)->data(Qt::UserRole).value<sqlb::StringVector>();
+    sqlb::ConstraintPtr constraint = ui->tableConstraints->item(row, kConstraintName)->data(Qt::UserRole).value<sqlb::ConstraintPtr>();
+
+    // Remove the constraint. If there is more than one constraint with this combination of columns and constraint type, only delete the first one.
+    m_table.removeConstraint(columns, constraint);
+    ui->tableConstraints->removeRow(ui->tableConstraints->currentRow());
+
+    // Update SQL and view
+    updateSqlText();
+    populateFields();
+}

src/EditTableDialog.h

@@ -72,6 +72,7 @@ private slots:
     void moveDown();
     void setWithoutRowid(bool without_rowid);
     void changeSchema(const QString& schema);
+    void removeConstraint();
 
 private:
     Ui::EditTableDialog* ui;

src/EditTableDialog.ui

@@ -618,6 +618,22 @@
     </hint>
    </hints>
   </connection>
+  <connection>
+   <sender>buttonRemoveConstraint</sender>
+   <signal>clicked()</signal>
+   <receiver>EditTableDialog</receiver>
+   <slot>removeConstraint()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>186</x>
+     <y>155</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>647</x>
+     <y>157</y>
+    </hint>
+   </hints>
+  </connection>
  </connections>
  <slots>
   <slot>fieldSelectionChanged()</slot>
@@ -630,5 +646,6 @@
   <slot>moveDown()</slot>
   <slot>setWithoutRowid(bool)</slot>
   <slot>changeSchema(QString)</slot>
+  <slot>removeConstraint()</slot>
  </slots>
 </ui>

src/sql/sqlitetypes.cpp

@@ -509,6 +509,20 @@ void Table::setConstraint(const StringVector& vStrFields, ConstraintPtr constrai
     addConstraint(vStrFields, constraint);
 }
 
+void Table::removeConstraint(const StringVector& vStrFields, ConstraintPtr constraint)
+{
+    for(auto it = m_constraints.begin();it!=m_constraints.end();++it)
+    {
+        if(it->first == vStrFields && it->second->toSql(vStrFields) == constraint->toSql(vStrFields))
+        {
+            m_constraints.erase(it);
+
+            // Only remove the first constraint matching these criteria
+            return;
+        }
+    }
+}
+
 void Table::removeConstraints(const StringVector& vStrFields, Constraint::ConstraintTypes type)
 {
     for(auto it = m_constraints.begin();it!=m_constraints.end();)

src/sql/sqlitetypes.h

@@ -337,7 +337,8 @@ public:
 
     void addConstraint(const StringVector& vStrFields, ConstraintPtr constraint);
     void setConstraint(const StringVector& vStrFields, ConstraintPtr constraint);
-    void removeConstraints(const StringVector& vStrFields = StringVector(), Constraint::ConstraintTypes type = Constraint::NoType); //! Only removes the first constraint, if any
+    void removeConstraint(const StringVector& vStrFields, ConstraintPtr constraint);
+    void removeConstraints(const StringVector& vStrFields = StringVector(), Constraint::ConstraintTypes type = Constraint::NoType);
     ConstraintPtr constraint(const StringVector& vStrFields = StringVector(), Constraint::ConstraintTypes type = Constraint::NoType) const;   //! Only returns the first constraint, if any
     std::vector<ConstraintPtr> constraints(const StringVector& vStrFields = StringVector(), Constraint::ConstraintTypes type = Constraint::NoType) const;
     ConstraintMap allConstraints() const { return m_constraints; }