Get database read working fully in Python

Author: JakeRoggenbuck

python/lstore/query.py

@@ -33,7 +33,7 @@ def delete(self, primary_key: int):
     """
 
     def insert(self, *columns):
-        self.rquery.insert(columns)
+        return self.rquery.insert(columns)
 
     """
     # Read matching record with specified search key
@@ -48,7 +48,7 @@ def insert(self, *columns):
     def select(
         self, search_key: Any, search_key_index: int, projected_columns_index: int
     ):
-        self.rquery.select(search_key, search_key_index, projected_columns_index)
+        return self.rquery.select(search_key, search_key_index, projected_columns_index)
 
     """
     # Read matching record with specified search key

simple_tester.py

@@ -5,5 +5,12 @@
 grades_table = db.create_table('Grades', 5, 0)
 query = Query(grades_table)
 
+recs = []
+
 for i in range(0, 10):
-    query.insert(10 + i, 93, 0, 0, 0)
+    rec = query.insert(10 + i, 93, 0, 0, 0)
+    recs.append(rec)
+
+for rec in recs:
+    vals = query.select(rec.rid, 0, 0)
+    print(vals)

src/container.rs

@@ -166,6 +166,20 @@ impl BaseContainer {
             addresses: addresses.clone(),
         }
     }
+
+    pub fn read_record(&self, record: Record) -> Vec<u64> {
+        let mut values = Vec::<u64>::new();
+
+        let addrs = record.addresses.lock().unwrap();
+        let addrs_clone = addrs.clone();
+        for addr in addrs_clone {
+            let a = addr.page.lock().unwrap();
+            let b = a.read(addr.offset as usize);
+            values.push(b.expect("Value should be there"));
+        }
+
+        values
+    }
 }
 
 #[derive(Clone)]

src/database.rs

@@ -28,19 +28,21 @@ impl PageRange {
         self.base_container.insert_record(new_rid, values)
     }
 
-    fn read(&self, rid: u64) -> Option<Vec<u64>> {
-        // self.base_container.read(rid);
-        Some(vec![])
+    fn read(&self, record: Record) -> Option<Vec<u64>> {
+        Some(self.base_container.read_record(record))
     }
 }
 
+#[derive(Debug, Clone)]
 pub struct RecordAddress {
     pub page: Arc<Mutex<PhysicalPage>>,
     pub offset: u64,
 }
 
+#[derive(Debug, Clone)]
 #[pyclass]
 pub struct Record {
+    #[pyo3(get)]
     pub rid: u64,
     pub addresses: Arc<Mutex<Vec<RecordAddress>>>,
 }
@@ -52,8 +54,8 @@ pub struct RTable {
     pub primary_key_column: i64,
     pub page_range: PageRange,
 
-    // TODO: Fix this to be the correct usage
-    pub page_directory: HashMap<i64, i64>,
+    // Map RIDs to Records
+    pub page_directory: HashMap<u64, Record>,
     pub num_records: u64,
 
     #[pyo3(get)]
@@ -63,12 +65,22 @@ pub struct RTable {
 impl RTable {
     pub fn write(&mut self, values: Vec<u64>) -> Record {
         let rec = self.page_range.write(self.num_records, values);
+
+        // Save the RID -> Record so it can later be read
+        self.page_directory.insert(self.num_records, rec.clone());
+
         self.num_records += 1;
         return rec;
     }
 
     pub fn read(&self, rid: u64) -> Option<Vec<u64>> {
-        self.page_range.read(rid)
+        let rec = self.page_directory.get(&rid);
+
+        // If the rec exists in the page_directory, return the read values
+        match rec {
+            Some(r) => self.page_range.read(r.clone()),
+            None => None,
+        }
     }
 
     fn _merge() {

src/query.rs

@@ -26,7 +26,8 @@ impl RQuery {
         &mut self,
         search_key: i64,
         _search_key_index: i64,
-        projected_columns_index: Vec<i64>,
+        // TODO: I think this should be a vec, but I'm not sure
+        projected_columns_index: i64,
     ) -> Vec<u64> {
         self.table.read(search_key as u64).unwrap()
     }