Add support for Postgres ALTER TYPE (apache#1727)

jvatic · ayman-sigma · commit d6cab3d8cd39 · 2025-04-10T14:47:55.000-07:00
diff --git a/src/ast/ddl.rs b/src/ast/ddl.rs
@@ -640,6 +640,95 @@ impl fmt::Display for AlterIndexOperation {
     }
 }
 
+/// An `ALTER TYPE` statement (`Statement::AlterType`)
+#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
+pub struct AlterType {
+    pub name: ObjectName,
+    pub operation: AlterTypeOperation,
+}
+
+/// An [AlterType] operation
+#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
+pub enum AlterTypeOperation {
+    Rename(AlterTypeRename),
+    AddValue(AlterTypeAddValue),
+    RenameValue(AlterTypeRenameValue),
+}
+
+/// See [AlterTypeOperation::Rename]
+#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
+pub struct AlterTypeRename {
+    pub new_name: Ident,
+}
+
+/// See [AlterTypeOperation::AddValue]
+#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
+pub struct AlterTypeAddValue {
+    pub if_not_exists: bool,
+    pub value: Ident,
+    pub position: Option<AlterTypeAddValuePosition>,
+}
+
+/// See [AlterTypeAddValue]
+#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
+pub enum AlterTypeAddValuePosition {
+    Before(Ident),
+    After(Ident),
+}
+
+/// See [AlterTypeOperation::RenameValue]
+#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
+pub struct AlterTypeRenameValue {
+    pub from: Ident,
+    pub to: Ident,
+}
+
+impl fmt::Display for AlterTypeOperation {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            Self::Rename(AlterTypeRename { new_name }) => {
+                write!(f, "RENAME TO {new_name}")
+            }
+            Self::AddValue(AlterTypeAddValue {
+                if_not_exists,
+                value,
+                position,
+            }) => {
+                write!(f, "ADD VALUE")?;
+                if *if_not_exists {
+                    write!(f, " IF NOT EXISTS")?;
+                }
+                write!(f, " {value}")?;
+                match position {
+                    Some(AlterTypeAddValuePosition::Before(neighbor_value)) => {
+                        write!(f, " BEFORE {neighbor_value}")?;
+                    }
+                    Some(AlterTypeAddValuePosition::After(neighbor_value)) => {
+                        write!(f, " AFTER {neighbor_value}")?;
+                    }
+                    None => {}
+                };
+                Ok(())
+            }
+            Self::RenameValue(AlterTypeRenameValue { from, to }) => {
+                write!(f, "RENAME VALUE {from} TO {to}")
+            }
+        }
+    }
+}
+
 /// An `ALTER COLUMN` (`Statement::AlterTable`) operation
 #[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
diff --git a/src/ast/mod.rs b/src/ast/mod.rs
@@ -48,13 +48,15 @@ pub use self::dcl::{
 };
 pub use self::ddl::{
     AlterColumnOperation, AlterConnectorOwner, AlterIndexOperation, AlterPolicyOperation,
-    AlterTableOperation, ClusteredBy, ColumnDef, ColumnOption, ColumnOptionDef, ColumnPolicy,
-    ColumnPolicyProperty, ConstraintCharacteristics, CreateConnector, CreateFunction, Deduplicate,
-    DeferrableInitial, DropBehavior, GeneratedAs, GeneratedExpressionMode, IdentityParameters,
-    IdentityProperty, IdentityPropertyFormatKind, IdentityPropertyKind, IdentityPropertyOrder,
-    IndexOption, IndexType, KeyOrIndexDisplay, NullsDistinctOption, Owner, Partition,
-    ProcedureParam, ReferentialAction, TableConstraint, TagsColumnOption,
-    UserDefinedTypeCompositeAttributeDef, UserDefinedTypeRepresentation, ViewColumnDef,
+    AlterTableOperation, AlterType, AlterTypeAddValue, AlterTypeAddValuePosition,
+    AlterTypeOperation, AlterTypeRename, AlterTypeRenameValue, ClusteredBy, ColumnDef,
+    ColumnOption, ColumnOptionDef, ColumnPolicy, ColumnPolicyProperty, ConstraintCharacteristics,
+    CreateConnector, CreateFunction, Deduplicate, DeferrableInitial, DropBehavior, GeneratedAs,
+    GeneratedExpressionMode, IdentityParameters, IdentityProperty, IdentityPropertyFormatKind,
+    IdentityPropertyKind, IdentityPropertyOrder, IndexOption, IndexType, KeyOrIndexDisplay,
+    NullsDistinctOption, Owner, Partition, ProcedureParam, ReferentialAction, TableConstraint,
+    TagsColumnOption, UserDefinedTypeCompositeAttributeDef, UserDefinedTypeRepresentation,
+    ViewColumnDef,
 };
 pub use self::dml::{CreateIndex, CreateTable, Delete, Insert};
 pub use self::operator::{BinaryOperator, UnaryOperator};
@@ -2709,6 +2711,11 @@ pub enum Statement {
         with_options: Vec<SqlOption>,
     },
     /// ```sql
+    /// ALTER TYPE
+    /// See [PostgreSQL](https://www.postgresql.org/docs/current/sql-altertype.html)
+    /// ```
+    AlterType(AlterType),
+    /// ```sql
     /// ALTER ROLE
     /// ```
     AlterRole {
@@ -4456,6 +4463,9 @@ impl fmt::Display for Statement {
                 }
                 write!(f, " AS {query}")
             }
+            Statement::AlterType(AlterType { name, operation }) => {
+                write!(f, "ALTER TYPE {name} {operation}")
+            }
             Statement::AlterRole { name, operation } => {
                 write!(f, "ALTER ROLE {name} {operation}")
             }
diff --git a/src/ast/spans.rs b/src/ast/spans.rs
@@ -215,6 +215,7 @@ impl Spanned for Values {
 /// - [Statement::CopyIntoSnowflake]
 /// - [Statement::CreateSecret]
 /// - [Statement::CreateRole]
+/// - [Statement::AlterType]
 /// - [Statement::AlterRole]
 /// - [Statement::AttachDatabase]
 /// - [Statement::AttachDuckDBDatabase]
@@ -427,6 +428,7 @@ impl Spanned for Statement {
                     .chain(with_options.iter().map(|i| i.span())),
             ),
             // These statements need to be implemented
+            Statement::AlterType { .. } => Span::empty(),
             Statement::AlterRole { .. } => Span::empty(),
             Statement::AttachDatabase { .. } => Span::empty(),
             Statement::AttachDuckDBDatabase { .. } => Span::empty(),
diff --git a/src/dialect/postgresql.rs b/src/dialect/postgresql.rs
@@ -28,7 +28,6 @@
 // limitations under the License.
 use log::debug;
 
-use crate::ast::{ObjectName, Statement, UserDefinedTypeRepresentation};
 use crate::dialect::{Dialect, Precedence};
 use crate::keywords::Keyword;
 use crate::parser::{Parser, ParserError};
@@ -135,15 +134,6 @@ impl Dialect for PostgreSqlDialect {
         }
     }
 
-    fn parse_statement(&self, parser: &mut Parser) -> Option<Result<Statement, ParserError>> {
-        if parser.parse_keyword(Keyword::CREATE) {
-            parser.prev_token(); // unconsume the CREATE in case we don't end up parsing anything
-            parse_create(parser)
-        } else {
-            None
-        }
-    }
-
     fn supports_filter_during_aggregation(&self) -> bool {
         true
     }
@@ -259,37 +249,3 @@ impl Dialect for PostgreSqlDialect {
         true
     }
 }
-
-pub fn parse_create(parser: &mut Parser) -> Option<Result<Statement, ParserError>> {
-    let name = parser.maybe_parse(|parser| -> Result<ObjectName, ParserError> {
-        parser.expect_keyword_is(Keyword::CREATE)?;
-        parser.expect_keyword_is(Keyword::TYPE)?;
-        let name = parser.parse_object_name(false)?;
-        parser.expect_keyword_is(Keyword::AS)?;
-        parser.expect_keyword_is(Keyword::ENUM)?;
-        Ok(name)
-    });
-
-    match name {
-        Ok(name) => name.map(|name| parse_create_type_as_enum(parser, name)),
-        Err(e) => Some(Err(e)),
-    }
-}
-
-// https://www.postgresql.org/docs/current/sql-createtype.html
-pub fn parse_create_type_as_enum(
-    parser: &mut Parser,
-    name: ObjectName,
-) -> Result<Statement, ParserError> {
-    if !parser.consume_token(&Token::LParen) {
-        return parser.expected("'(' after CREATE TYPE AS ENUM", parser.peek_token());
-    }
-
-    let labels = parser.parse_comma_separated0(|p| p.parse_identifier(), Token::RParen)?;
-    parser.expect_token(&Token::RParen)?;
-
-    Ok(Statement::CreateType {
-        name,
-        representation: UserDefinedTypeRepresentation::Enum { labels },
-    })
-}
diff --git a/src/parser/mod.rs b/src/parser/mod.rs
@@ -8052,6 +8052,7 @@ impl<'a> Parser<'a> {
     pub fn parse_alter(&mut self) -> Result<Statement, ParserError> {
         let object_type = self.expect_one_of_keywords(&[
             Keyword::VIEW,
+            Keyword::TYPE,
             Keyword::TABLE,
             Keyword::INDEX,
             Keyword::ROLE,
@@ -8060,6 +8061,7 @@ impl<'a> Parser<'a> {
         ])?;
         match object_type {
             Keyword::VIEW => self.parse_alter_view(),
+            Keyword::TYPE => self.parse_alter_type(),
             Keyword::TABLE => {
                 let if_exists = self.parse_keywords(&[Keyword::IF, Keyword::EXISTS]);
                 let only = self.parse_keyword(Keyword::ONLY); // [ ONLY ]
@@ -8132,6 +8134,55 @@ impl<'a> Parser<'a> {
         })
     }
 
+    /// Parse a [Statement::AlterType]
+    pub fn parse_alter_type(&mut self) -> Result<Statement, ParserError> {
+        let name = self.parse_object_name(false)?;
+
+        if self.parse_keywords(&[Keyword::RENAME, Keyword::TO]) {
+            let new_name = self.parse_identifier()?;
+            Ok(Statement::AlterType(AlterType {
+                name,
+                operation: AlterTypeOperation::Rename(AlterTypeRename { new_name }),
+            }))
+        } else if self.parse_keywords(&[Keyword::ADD, Keyword::VALUE]) {
+            let if_not_exists = self.parse_keywords(&[Keyword::IF, Keyword::NOT, Keyword::EXISTS]);
+            let new_enum_value = self.parse_identifier()?;
+            let position = if self.parse_keyword(Keyword::BEFORE) {
+                Some(AlterTypeAddValuePosition::Before(self.parse_identifier()?))
+            } else if self.parse_keyword(Keyword::AFTER) {
+                Some(AlterTypeAddValuePosition::After(self.parse_identifier()?))
+            } else {
+                None
+            };
+
+            Ok(Statement::AlterType(AlterType {
+                name,
+                operation: AlterTypeOperation::AddValue(AlterTypeAddValue {
+                    if_not_exists,
+                    value: new_enum_value,
+                    position,
+                }),
+            }))
+        } else if self.parse_keywords(&[Keyword::RENAME, Keyword::VALUE]) {
+            let existing_enum_value = self.parse_identifier()?;
+            self.expect_keyword(Keyword::TO)?;
+            let new_enum_value = self.parse_identifier()?;
+
+            Ok(Statement::AlterType(AlterType {
+                name,
+                operation: AlterTypeOperation::RenameValue(AlterTypeRenameValue {
+                    from: existing_enum_value,
+                    to: new_enum_value,
+                }),
+            }))
+        } else {
+            return self.expected_ref(
+                "{RENAME TO | { RENAME | ADD } VALUE}",
+                self.peek_token_ref(),
+            );
+        }
+    }
+
     /// Parse a `CALL procedure_name(arg1, arg2, ...)`
     /// or `CALL procedure_name` statement
     pub fn parse_call(&mut self) -> Result<Statement, ParserError> {
@@ -14232,6 +14283,10 @@ impl<'a> Parser<'a> {
         let name = self.parse_object_name(false)?;
         self.expect_keyword_is(Keyword::AS)?;
 
+        if self.parse_keyword(Keyword::ENUM) {
+            return self.parse_create_type_enum(name);
+        }
+
         let mut attributes = vec![];
         if !self.consume_token(&Token::LParen) || self.consume_token(&Token::RParen) {
             return Ok(Statement::CreateType {
@@ -14268,6 +14323,20 @@ impl<'a> Parser<'a> {
         })
     }
 
+    /// Parse remainder of `CREATE TYPE AS ENUM` statement (see [Statement::CreateType] and [Self::parse_create_type])
+    ///
+    /// See [PostgreSQL](https://www.postgresql.org/docs/current/sql-createtype.html)
+    pub fn parse_create_type_enum(&mut self, name: ObjectName) -> Result<Statement, ParserError> {
+        self.expect_token(&Token::LParen)?;
+        let labels = self.parse_comma_separated0(|p| p.parse_identifier(), Token::RParen)?;
+        self.expect_token(&Token::RParen)?;
+
+        Ok(Statement::CreateType {
+            name,
+            representation: UserDefinedTypeRepresentation::Enum { labels },
+        })
+    }
+
     fn parse_parenthesized_identifiers(&mut self) -> Result<Vec<Ident>, ParserError> {
         self.expect_token(&Token::LParen)?;
         let partitions = self.parse_comma_separated(|p| p.parse_identifier())?;
diff --git a/tests/sqlparser_postgres.rs b/tests/sqlparser_postgres.rs
