Implement NULL columns

src/sqlsyntax/ast.rs

@@ -136,7 +136,7 @@ pub struct CreateTableColumnConstraint {
     pub constraint: CreateTableColumnConstraintType
 }
 
-#[derive(Debug)]
+#[derive(Debug, PartialEq)]
 pub enum CreateTableColumnConstraintType {
     PrimaryKey,
     Unique,

src/tempdb/mod.rs

@@ -6,7 +6,7 @@
 use std::borrow::Cow;
 use std::collections::BTreeSet;
 
-use columnvalueops::ColumnValueOps;
+use columnvalueops::{ColumnValueOps, ColumnValueOpsExt};
 use databaseinfo::{DatabaseInfo, TableInfo, ColumnInfo};
 use databasestorage::{Group, DatabaseStorage};
 use identifier::Identifier;
@@ -84,6 +84,17 @@ impl<'a> Group for ScanGroup<'a> {
             let mut key_offset = 8;
 
             let v: Vec<Variant> = columns.iter().map(|column| {
+                let is_null = if column.nullable {
+                    let flag = raw_key[key_offset];
+                    key_offset += 1;
+                    flag != 0
+                } else {
+                    false
+                };
+
+                if is_null {
+                    ColumnValueOpsExt::null()
+                } else {
                     let size = match column.dbtype.get_fixed_length() {
                         Some(l) => l as usize,
                         None => {
@@ -99,6 +110,7 @@ impl<'a> Group for ScanGroup<'a> {
                     let value = ColumnValueOps::from_bytes(column.dbtype, bytes.into_cow()).unwrap();
                     key_offset += size;
                     value
+                }
             }).collect();
 
             v.into_cow()
@@ -160,10 +172,15 @@ impl TempDb {
 
             let dbtype = try!(DbType::from_identifier(&type_name, type_array_size).ok_or(format!("{} is not a valid column type", type_name)));
 
+            let nullable = column.constraints.iter().any(|c| {
+                c.constraint == ast::CreateTableColumnConstraintType::Nullable
+            });
+
             Ok(table::Column {
                 offset: i as u32,
                 name: name,
-                dbtype: dbtype
+                dbtype: dbtype,
+                nullable: nullable
             })
         }).collect();
 
@@ -186,8 +203,8 @@ impl TempDb {
 
         let mut table = try!(self.get_table_mut(stmt.table));
 
-        let column_types: Vec<DbType> = table.get_columns().iter().map(|c| {
-            c.dbtype
+        let column_types: Vec<(DbType, bool)> = table.get_columns().iter().map(|c| {
+            (c.dbtype, c.nullable)
         }).collect();
 
         let ast_index_to_column_index: Vec<u32> = match stmt.into_columns {
@@ -220,7 +237,7 @@ impl TempDb {
                         return Err(format!("INSERT value contains wrong amount of columns"));
                     }
 
-                    let iter = column_types.iter().enumerate().map(|(i, &dbtype)| {
+                    let iter = column_types.iter().enumerate().map(|(i, &(dbtype, nullable))| {
                         let ast_index = column_index_to_ast_index.get(&i);
 
                         match ast_index {
@@ -228,12 +245,13 @@ impl TempDb {
                                 // TODO - allocate buffer outside of loop
                                 let mut buf = Vec::new();
                                 let expr = &row[*ast_index];
-                                ast_expression_to_data(expr, dbtype, &mut buf);
-                                Cow::Owned(buf)
+                                let is_null = ast_expression_to_data(expr, dbtype, nullable, &mut buf);
+                                (Cow::Owned(buf), is_null)
                             },
                             None => {
                                 // use default value for column type
-                                dbtype.get_default()
+                                let is_null = if nullable { Some(true) } else { None };
+                                (dbtype.get_default(), is_null)
                             }
                         }
                     });
@@ -313,11 +331,14 @@ impl TempDb {
     }
 }
 
-fn ast_expression_to_data(expr: &ast::Expression, column_type: DbType, buf: &mut Vec<u8>) {
+fn ast_expression_to_data(expr: &ast::Expression, column_type: DbType, nullable: bool, buf: &mut Vec<u8>) -> Option<bool> {
     use sqlsyntax::ast::Expression::*;
     use std::borrow::IntoCow;
 
     let value: Variant = match expr {
+        &Null => {
+            ColumnValueOpsExt::null()
+        },
         &StringLiteral(ref s) => {
             let r: &str = &s;
             ColumnValueOps::from_string_literal(r.into_cow()).unwrap()
@@ -329,6 +350,17 @@ fn ast_expression_to_data(expr: &ast::Expression, column_type: DbType, buf: &mut
         _ => unimplemented!()
     };
 
+    match (value.is_null(), nullable) {
+        (true, true) => Some(true),
+        (true, false) => {
+            // TODO: return error
+            unimplemented!()
+        },
+        (false, nullable) => {
             let bytes = value.to_bytes(column_type).unwrap();
             buf.push_all(&bytes);
+
+            if nullable { Some(false) } else { None }
+        }
+    }
 }

src/tempdb/table.rs

@@ -36,6 +36,7 @@ pub struct Column {
     pub offset: u32,
     pub name: Identifier,
     pub dbtype: DbType,
+    pub nullable: bool
 }
 
 impl TableInfo for Table {
@@ -63,7 +64,7 @@ impl TableInfo for Table {
 impl Table {
     /// rowid is automatically added, and is not included as a specified column
     pub fn insert_row<'a, I>(&mut self, column_data: I) -> Result<(), UpdateError>
-    where I: ExactSizeIterator, I: Iterator<Item = Cow<'a, [u8]>>
+    where I: ExactSizeIterator, I: Iterator<Item = (Cow<'a, [u8]>, Option<bool>)>
     {
         // TODO - remove Cow in favor of yielding either `u8` slices or `u8` iterators
 
@@ -80,13 +81,29 @@ impl Table {
 
         trace!("columns: {:?}", self.columns);
 
-        for (column, data_cow) in self.columns.iter().zip(column_data) {
+        for (column, (data_cow, is_null)) in self.columns.iter().zip(column_data) {
             let data: &[u8] = &*data_cow;
 
             trace!("column data for {}: {:?}", column.name, data);
 
             let len = data.len() as u64;
 
+            let append_data = match is_null {
+                Some(true) => {
+                    assert_eq!(len, 0);
+                    key.push(1);
+
+                    false
+                },
+                Some(false) => {
+                    key.push(0);
+
+                    true
+                },
+                None => true
+            };
+
+            if append_data {
                 if column.dbtype.is_valid_length(len) {
                     if column.dbtype.is_variable_length() {
                         let mut buf = [0; 8];
@@ -94,6 +111,14 @@ impl Table {
                         lengths.push_all(&buf);
                     }
 
+                    assert_eq!(column.nullable, is_null.is_some());
+
+                    if let Some(is_null) = is_null {
+                        if is_null {
+                        }
+
+                    }
+
                     key.push_all(data);
                 } else {
                     return Err(UpdateError::ValidationError {
@@ -101,6 +126,7 @@ impl Table {
                     });
                 }
             }
+        }
 
         key.extend(lengths);