I'm not able to delete elements of these vectors - c++

Question

I want to delete every element at a certain index (that corresponds to a certain content), but I'm getting a segmentation fault... This is the structure of my code and the method deleteRecord is what I've tried but doesn't work:
class Tab {
public:
Tab();
~Tab() {};
bool colIsPresent(const string & col_name);
template <typename S> void deleteRecord(S & content, const string & col_name) {
int delete_pos;
if (!this->colIsPresent(col_name)) return;
const auto & it_columns = _columns.find(col_name);
if (it_columns != _columns.end()) {
auto ci = dynamic_cast<ColumnImpl<S> *>(it_columns->second.get());
if (ci != nullptr) {
for (int i = 0; i < ci->getData().size(); i++) {
if (ci->getData()[i] == content) {
delete_pos = i;
}
for (auto & it_columns_2 : _columns) {
auto ci2 = dynamic_cast<ColumnImpl<S> *>(it_columns_2.second.get());
ci2->getData().erase(ci2->getData().begin() + delete_pos);
}
}
}
}
}
private:
map<string, shared_ptr<Column>> _columns;
};
template <typename T> class ColumnImpl : public Column {
public:
ColumnImpl() : Column() {}
ColumnImpl(const T& to_set);
vector<T> & getData() { return _data; }
protected:
vector<T> _data;
};
class Column {
public:
Column();
virtual ~Column() {};
virtual string getType() = 0;
};
class Database {
public:
Database();
~Database();
bool tabIsPresent(const string & tab_name);
template <typename S> void deleteRecordFromTab(const string & tab_name, S & content, const string & col_name) {
const auto & it_target_tab = _tables.find(tab_name);
it_target_tab->second.deleteRecord(content, col_name);
}
private:
map<string, Tab> _tables;
};
Reproducible example:
Database data_base;
string tab = "EX_TAB", str1 = "STR_EX1", str2 = "STR_EX2", age = "AGE", name = "NAME", integer = "INT", text = "TEXT";
int a = 17, b = 18;
data_base.createNewTable(tab);
data_base.addColumnToTab(tab, age, integer);
data_base.addColumnToTab(tab, name, text);
data_base.addElemToColOfTab(tab, age, a);
data_base.addElemToColOfTab(tab, age, b);
data_base.addElemToColOfTab(tab, name, str1);
data_base.addElemToColOfTab(tab, name, str2);
data_base.deleteRecordFromTab(tab, str1, name);
// createNewTable creates a new table
// addColumnToTab adds a new column of the right type to _columns
// addElemToColumnOfTab adds an element to the targeted column