feat: support current_timestamp and now as default constrains (#2690)

Signed-off-by: Ruihang Xia <[email protected]>

src/datatypes/src/schema/constraint.rs

@@ -24,7 +24,9 @@ use crate::value::Value;
 use crate::vectors::operations::VectorOp;
 use crate::vectors::{TimestampMillisecondVector, VectorRef};
 
-const CURRENT_TIMESTAMP: &str = "current_timestamp()";
+const CURRENT_TIMESTAMP: &str = "current_timestamp";
+const CURRENT_TIMESTAMP_FN: &str = "current_timestamp()";
+const NOW_FN: &str = "now()";
 
 /// Column's default constraint.
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
@@ -77,7 +79,7 @@ impl ColumnDefaultConstraint {
         match self {
             ColumnDefaultConstraint::Function(expr) => {
                 ensure!(
-                    expr == CURRENT_TIMESTAMP,
+                    expr == CURRENT_TIMESTAMP || expr == CURRENT_TIMESTAMP_FN || expr == NOW_FN,
                     error::UnsupportedDefaultExprSnafu { expr }
                 );
                 ensure!(
@@ -130,7 +132,9 @@ impl ColumnDefaultConstraint {
                 match &expr[..] {
                     // TODO(dennis): we only supports current_timestamp right now,
                     //   it's better to use a expression framework in future.
-                    CURRENT_TIMESTAMP => create_current_timestamp_vector(data_type, num_rows),
+                    CURRENT_TIMESTAMP | CURRENT_TIMESTAMP_FN | NOW_FN => {
+                        create_current_timestamp_vector(data_type, num_rows)
+                    }
                     _ => error::UnsupportedDefaultExprSnafu { expr }.fail(),
                 }
             }
@@ -160,7 +164,9 @@ impl ColumnDefaultConstraint {
                 // Functions should also ensure its return value is not null when
                 // is_nullable is true.
                 match &expr[..] {
-                    CURRENT_TIMESTAMP => create_current_timestamp(data_type),
+                    CURRENT_TIMESTAMP | CURRENT_TIMESTAMP_FN | NOW_FN => {
+                        create_current_timestamp(data_type)
+                    }
                     _ => error::UnsupportedDefaultExprSnafu { expr }.fail(),
                 }
             }

tests/cases/standalone/common/create/current_timestamp.result

@@ -0,0 +1,28 @@
+create table t1 (ts timestamp time index default CURRENT_TIMESTAMP);
+
+Affected Rows: 0
+
+create table t2 (ts timestamp time index default currEnt_tImEsTamp());
+
+Affected Rows: 0
+
+create table t3 (ts timestamp time index default now());
+
+Affected Rows: 0
+
+create table t4 (ts timestamp time index default now);
+
+Error: 1001(Unsupported), Unsupported expr in default constraint: Identifier(Ident { value: "now", quote_style: None }) for column: ts
+
+drop table t1;
+
+Affected Rows: 0
+
+drop table t2;
+
+Affected Rows: 0
+
+drop table t3;
+
+Affected Rows: 0
+

tests/cases/standalone/common/create/current_timestamp.sql

@@ -0,0 +1,11 @@
+create table t1 (ts timestamp time index default CURRENT_TIMESTAMP);
+
+create table t2 (ts timestamp time index default currEnt_tImEsTamp());
+
+create table t3 (ts timestamp time index default now());
+
+create table t4 (ts timestamp time index default now);
+
+drop table t1;
+drop table t2;
+drop table t3;