feat(type): add support for Decimal type in database (#66)

Co-authored-by: Kould <2435992353@qq.com>

Author: loloxwg

Cargo.toml

@@ -32,6 +32,7 @@ comfy-table = "7.0.1"
 bytes = "*"
 kip_db = "0.1.2-alpha.15"
 async-recursion = "1.0.5"
+rust_decimal = "1"
 
 [dev-dependencies]
 tokio-test = "0.4.2"

src/binder/insert.rs

@@ -50,7 +50,7 @@ impl<S: Storage> Binder<S> {
                     match &self.bind_expr(expr).await? {
                         ScalarExpression::Constant(value) => {
                             // Check if the value length is too long
-                            value.check_length(columns[i].datatype())?;
+                            value.check_len(columns[i].datatype())?;
                             let cast_value = DataValue::clone(value)
                                 .cast(columns[i].datatype())?;
                             row.push(Arc::new(cast_value))

src/binder/update.rs

@@ -44,7 +44,7 @@ impl<S: Storage> Binder<S> {
                         bind_table_name.as_ref()
                     ).await? {
                         ScalarExpression::ColumnRef(catalog) => {
-                            value.check_length(catalog.datatype())?;
+                            value.check_len(catalog.datatype())?;
                             columns.push(catalog);
                             row.push(value.clone());
                         },

src/db.rs

@@ -186,6 +186,9 @@ mod test {
         let _ = kipsql.run("create table t2 (c int primary key, d int unsigned null, e datetime)").await?;
         let _ = kipsql.run("insert into t1 (a, b, k) values (-99, 1, 1), (-1, 2, 2), (5, 2, 2)").await?;
         let _ = kipsql.run("insert into t2 (d, c, e) values (2, 1, '2021-05-20 21:00:00'), (3, 4, '2023-09-10 00:00:00')").await?;
+        let _ = kipsql.run("create table t3 (a int primary key, b decimal(4,2))").await?;
+        let _ = kipsql.run("insert into t3 (a, b) values (1, 1111), (2, 2.01), (3, 3.00)").await?;
+        let _ = kipsql.run("insert into t3 (a, b) values (4, 4444), (5, 5222), (6, 1.00)").await?;
 
         println!("full t1:");
         let tuples_full_fields_t1 = kipsql.run("select * from t1").await?;
@@ -305,6 +308,10 @@ mod test {
         let tuples_show_tables = kipsql.run("show tables").await?;
         println!("{}", create_table(&tuples_show_tables));
 
+        println!("decimal:");
+        let tuples_decimal = kipsql.run("select * from t3").await?;
+        println!("{}", create_table(&tuples_decimal));
+
         Ok(())
     }
 }

src/expression/mod.rs

@@ -1,5 +1,5 @@
 use std::fmt;
-use std::fmt::Formatter;
+use std::fmt::{Debug, Formatter};
 use std::sync::Arc;
 use itertools::Itertools;
 

src/storage/table_codec.rs

@@ -146,6 +146,7 @@ mod tests {
     use std::ops::Bound;
     use std::sync::Arc;
     use itertools::Itertools;
+    use rust_decimal::Decimal;
     use crate::catalog::{ColumnCatalog, ColumnDesc, TableCatalog};
     use crate::storage::table_codec::{COLUMNS_ID_LEN, TableCodec};
     use crate::types::errors::TypeError;
@@ -159,7 +160,12 @@ mod tests {
                 "c1".into(),
                 false,
                 ColumnDesc::new(LogicalType::Integer, true)
-            )
+            ),
+            ColumnCatalog::new(
+                "c2".into(),
+                false,
+                ColumnDesc::new(LogicalType::Decimal(None,None), false)
+            ),
         ];
         let table_catalog = TableCatalog::new(Arc::new("t1".to_string()), columns).unwrap();
         let codec = TableCodec { table: table_catalog.clone() };
@@ -175,6 +181,7 @@ mod tests {
             columns: table_catalog.all_columns(),
             values: vec![
                 Arc::new(DataValue::Int32(Some(0))),
+                Arc::new(DataValue::Decimal(Some(Decimal::new(1, 0)))),
             ]
         };
 

src/types/errors.rs

@@ -46,4 +46,10 @@ pub enum TypeError {
         #[from]
         ParseError,
     ),
+    #[error("try from decimal")]
+    TryFromDecimal(
+        #[source]
+        #[from]
+        rust_decimal::Error,
+    ),
 }

src/types/mod.rs

@@ -7,6 +7,7 @@ use std::sync::atomic::Ordering::{Acquire, Release};
 use serde::{Deserialize, Serialize};
 
 use integer_encoding::FixedInt;
+use sqlparser::ast::ExactNumberInfo;
 use strum_macros::AsRefStr;
 
 use crate::types::errors::TypeError;
@@ -57,6 +58,8 @@ pub enum LogicalType {
     Varchar(Option<u32>),
     Date,
     DateTime,
+    // decimal (precision, scale)
+    Decimal(Option<u8>, Option<u8>),
 }
 
 impl LogicalType {
@@ -75,8 +78,9 @@ impl LogicalType {
             LogicalType::UBigint => Some(8),
             LogicalType::Float => Some(4),
             LogicalType::Double => Some(8),
-            /// Note: The non-fixed length type's raw_len is None
-            LogicalType::Varchar(_)=>None,
+            /// Note: The non-fixed length type's raw_len is None e.g. Varchar and Decimal
+            LogicalType::Varchar(_) => None,
+            LogicalType::Decimal(_, _) => Some(16),
             LogicalType::Date => Some(4),
             LogicalType::DateTime => Some(8),
         }
@@ -269,6 +273,7 @@ impl LogicalType {
             LogicalType::Varchar(_) => false,
             LogicalType::Date => matches!(to, LogicalType::DateTime | LogicalType::Varchar(_)),
             LogicalType::DateTime => matches!(to, LogicalType::Date | LogicalType::Varchar(_)),
+            LogicalType::Decimal(_, _) => false,
         }
     }
 }
@@ -296,6 +301,13 @@ impl TryFrom<sqlparser::ast::DataType> for LogicalType {
             sqlparser::ast::DataType::UnsignedBigInt(_) => Ok(LogicalType::UBigint),
             sqlparser::ast::DataType::Boolean => Ok(LogicalType::Boolean),
             sqlparser::ast::DataType::Datetime(_) => Ok(LogicalType::DateTime),
+            sqlparser::ast::DataType::Decimal(info) =>  match info {
+                    ExactNumberInfo::None => Ok(Self::Decimal(None, None)),
+                    ExactNumberInfo::Precision(p) => Ok(Self::Decimal(Some(p as u8), None)),
+                    ExactNumberInfo::PrecisionAndScale(p, s) => {
+                        Ok(Self::Decimal(Some(p as u8), Some(s as u8)))
+                    }
+            },
             other => Err(TypeError::NotImplementedSqlparserDataType(
                 other.to_string(),
             )),
@@ -313,7 +325,7 @@ impl std::fmt::Display for LogicalType {
 mod test {
     use std::sync::atomic::Ordering::Release;
 
-    use crate::types::{IdGenerator, ID_BUF, LogicalType};
+    use crate::types::{IdGenerator, ID_BUF};
 
     /// Tips: 由于IdGenerator为static全局性质生成的id，因此需要单独测试避免其他测试方法干扰
     #[test]