Error message

  • Deprecated function: Creation of dynamic property SelectQuery::$alterTags is deprecated in SelectQuery->addTag() (line 978 of /home/onlinede/public_html/includes/database/select.inc).
  • Deprecated function: Creation of dynamic property DatabaseCondition::$stringVersion is deprecated in DatabaseCondition->compile() (line 1887 of /home/onlinede/public_html/includes/database/query.inc).
  • Deprecated function: Creation of dynamic property DatabaseCondition::$stringVersion is deprecated in DatabaseCondition->compile() (line 1887 of /home/onlinede/public_html/includes/database/query.inc).
  • Deprecated function: Creation of dynamic property DatabaseCondition::$stringVersion is deprecated in DatabaseCondition->compile() (line 1887 of /home/onlinede/public_html/includes/database/query.inc).
  • Deprecated function: Creation of dynamic property DatabaseCondition::$stringVersion is deprecated in DatabaseCondition->compile() (line 1887 of /home/onlinede/public_html/includes/database/query.inc).
  • Deprecated function: Creation of dynamic property SelectQuery::$alterTags is deprecated in SelectQuery->addTag() (line 978 of /home/onlinede/public_html/includes/database/select.inc).
  • Deprecated function: Creation of dynamic property DatabaseCondition::$stringVersion is deprecated in DatabaseCondition->compile() (line 1887 of /home/onlinede/public_html/includes/database/query.inc).
  • Deprecated function: Creation of dynamic property DatabaseCondition::$stringVersion is deprecated in DatabaseCondition->compile() (line 1887 of /home/onlinede/public_html/includes/database/query.inc).
  • Deprecated function: Creation of dynamic property DatabaseCondition::$stringVersion is deprecated in DatabaseCondition->compile() (line 1887 of /home/onlinede/public_html/includes/database/query.inc).
  • Deprecated function: Creation of dynamic property DatabaseCondition::$stringVersion is deprecated in DatabaseCondition->compile() (line 1887 of /home/onlinede/public_html/includes/database/query.inc).
  • Deprecated function: Creation of dynamic property SelectQuery::$alterTags is deprecated in SelectQuery->addTag() (line 978 of /home/onlinede/public_html/includes/database/select.inc).
  • Deprecated function: Creation of dynamic property DatabaseCondition::$stringVersion is deprecated in DatabaseCondition->compile() (line 1887 of /home/onlinede/public_html/includes/database/query.inc).
  • Deprecated function: Creation of dynamic property DatabaseCondition::$stringVersion is deprecated in DatabaseCondition->compile() (line 1887 of /home/onlinede/public_html/includes/database/query.inc).
  • Deprecated function: Creation of dynamic property SelectQuery::$alterTags is deprecated in SelectQuery->addTag() (line 978 of /home/onlinede/public_html/includes/database/select.inc).
  • Deprecated function: Creation of dynamic property DatabaseCondition::$stringVersion is deprecated in DatabaseCondition->compile() (line 1887 of /home/onlinede/public_html/includes/database/query.inc).
  • Deprecated function: Creation of dynamic property DatabaseCondition::$stringVersion is deprecated in DatabaseCondition->compile() (line 1887 of /home/onlinede/public_html/includes/database/query.inc).

What is the difference between primary key and candidate key?

Every row of a table is identified uniquely by primary key. There is only one primary key for a table.

Primary Key is also a candidate key. By common convention, candidate key can be designated as primary and which can be used for any foreign key references.