MySQL: [[NOT] ENFORCED] in CHECK constraint

Add support for MySQL's `[[NOT] ENFORCED]` option for
CHECK constraints.

docs: https://dev.mysql.com/doc/refman/8.4/en/create-table.html

Author: MohamedAbdeen21

src/ast/ddl.rs

@@ -1026,10 +1026,13 @@ pub enum TableConstraint {
         on_update: Option<ReferentialAction>,
         characteristics: Option<ConstraintCharacteristics>,
     },
-    /// `[ CONSTRAINT <name> ] CHECK (<expr>)`
+    /// `[ CONSTRAINT <name> ] CHECK (<expr>) [[NOT] ENFORCED]`
     Check {
         name: Option<Ident>,
         expr: Box<Expr>,
+        /// MySQL-specific syntax
+        /// https://dev.mysql.com/doc/refman/8.4/en/create-table.html
+        enforced: Option<bool>,
     },
     /// MySQLs [index definition][1] for index creation. Not present on ANSI so, for now, the usage
     /// is restricted to MySQL, as no other dialects that support this syntax were found.
@@ -1157,8 +1160,17 @@ impl fmt::Display for TableConstraint {
                 }
                 Ok(())
             }
-            TableConstraint::Check { name, expr } => {
-                write!(f, "{}CHECK ({})", display_constraint_name(name), expr)
+            TableConstraint::Check {
+                name,
+                expr,
+                enforced,
+            } => {
+                write!(f, "{}CHECK ({})", display_constraint_name(name), expr)?;
+                if let Some(b) = enforced {
+                    write!(f, " {}", if *b { "ENFORCED" } else { "NOT ENFORCED" })
+                } else {
+                    Ok(())
+                }
             }
             TableConstraint::Index {
                 display_as_key,

src/ast/spans.rs

@@ -685,9 +685,11 @@ impl Spanned for TableConstraint {
                     .chain(on_update.iter().map(|i| i.span()))
                     .chain(characteristics.iter().map(|i| i.span())),
             ),
-            TableConstraint::Check { name, expr } => {
-                expr.span().union_opt(&name.as_ref().map(|i| i.span))
-            }
+            TableConstraint::Check {
+                name,
+                expr,
+                enforced: _,
+            } => expr.span().union_opt(&name.as_ref().map(|i| i.span)),
             TableConstraint::Index {
                 display_as_key: _,
                 name,

src/parser/mod.rs

@@ -8134,7 +8134,19 @@ impl<'a> Parser<'a> {
                 self.expect_token(&Token::LParen)?;
                 let expr = Box::new(self.parse_expr()?);
                 self.expect_token(&Token::RParen)?;
-                Ok(Some(TableConstraint::Check { name, expr }))
+
+                let enforced = match dialect_of!(self is GenericDialect | MySqlDialect) {
+                    true if self.parse_keywords(&[Keyword::NOT, Keyword::ENFORCED]) => Some(false),
+                    true if self.parse_keyword(Keyword::ENFORCED) => Some(true),
+                    // not MySQL, or is MySQL but not specified
+                    _ => None,
+                };
+
+                Ok(Some(TableConstraint::Check {
+                    name,
+                    expr,
+                    enforced,
+                }))
             }
             Token::Word(w)
                 if (w.keyword == Keyword::INDEX || w.keyword == Keyword::KEY)

tests/sqlparser_mysql.rs

@@ -4018,3 +4018,10 @@ fn parse_drop_index() {
         _ => unreachable!(),
     }
 }
+
+#[test]
+fn check_enforced() {
+    mysql().verified_stmt(
+        "CREATE TABLE t (a INT, b INT, c INT, CHECK (a > 0) NOT ENFORCED, CHECK (b > 0) ENFORCED, CHECK (c > 0))",
+    );
+}

tests/sqlparser_postgres.rs

@@ -5379,6 +5379,7 @@ fn parse_create_domain() {
                 op: BinaryOperator::Gt,
                 right: Box::new(Expr::Value(test_utils::number("0").into())),
             }),
+            enforced: None,
         }],
     });
 
@@ -5397,6 +5398,7 @@ fn parse_create_domain() {
                 op: BinaryOperator::Gt,
                 right: Box::new(Expr::Value(test_utils::number("0").into())),
             }),
+            enforced: None,
         }],
     });
 
@@ -5415,6 +5417,7 @@ fn parse_create_domain() {
                 op: BinaryOperator::Gt,
                 right: Box::new(Expr::Value(test_utils::number("0").into())),
             }),
+            enforced: None,
         }],
     });
 
@@ -5433,6 +5436,7 @@ fn parse_create_domain() {
                 op: BinaryOperator::Gt,
                 right: Box::new(Expr::Value(test_utils::number("0").into())),
             }),
+            enforced: None,
         }],
     });
 
@@ -5451,6 +5455,7 @@ fn parse_create_domain() {
                 op: BinaryOperator::Gt,
                 right: Box::new(Expr::Value(test_utils::number("0").into())),
             }),
+            enforced: None,
         }],
     });