refactor(cognitarium)!: make delete triples optional and enforce wher…

…e clause

Previously, delete triples was mandatory and the where clause optional. It was
incorrect with regards to the W3C specification of the SPARQL DELETE
query.

contracts/okp4-cognitarium/src/msg.rs

@@ -67,11 +67,12 @@ pub enum ExecuteMsg {
     DeleteData {
         /// The prefixes used in the operation.
         prefixes: Vec<Prefix>,
-        /// The items to delete.
+        /// Specifies the specific triple patterns to delete.
+        /// If nothing is provided, the patterns from the `where` clause are used for deletion.
         delete: Vec<TriplePattern>,
-        /// The WHERE clause to apply.
-        /// If not provided, all the RDF triples are considered.
-        r#where: Option<WhereClause>,
+        /// Defines the patterns that data (RDF triples) should match in order for it to be
+        /// considered for deletion.
+        r#where: WhereClause,
     },
 }
 
@@ -431,7 +432,7 @@ pub struct ConstructQuery {
 }
 
 /// # Prefix
-/// Represents a prefix in a [SelectQuery]. A prefix is a shortcut for a namespace used in the query.
+/// Represents a prefix, i.e. a shortcut for a namespace used in a query.
 #[cw_serde]
 pub struct Prefix {
     /// The prefix.