Add CREATE TRIGGER support for SQL Server (#1810)

Author: aharpervc

src/ast/mod.rs

@@ -2380,11 +2380,16 @@ impl fmt::Display for BeginEndStatements {
             end_token: AttachedToken(end_token),
         } = self;
 
-        write!(f, "{begin_token} ")?;
+        if begin_token.token != Token::EOF {
+            write!(f, "{begin_token} ")?;
+        }
         if !statements.is_empty() {
             format_statement_list(f, statements)?;
         }
-        write!(f, " {end_token}")
+        if end_token.token != Token::EOF {
+            write!(f, " {end_token}")?;
+        }
+        Ok(())
     }
 }
 
@@ -3729,7 +3734,12 @@ pub enum Statement {
     /// ```
     ///
     /// Postgres: <https://www.postgresql.org/docs/current/sql-createtrigger.html>
+    /// SQL Server: <https://learn.microsoft.com/en-us/sql/t-sql/statements/create-trigger-transact-sql>
     CreateTrigger {
+        /// True if this is a `CREATE OR ALTER TRIGGER` statement
+        ///
+        /// [MsSql](https://learn.microsoft.com/en-us/sql/t-sql/statements/create-trigger-transact-sql?view=sql-server-ver16#arguments)
+        or_alter: bool,
         /// The `OR REPLACE` clause is used to re-create the trigger if it already exists.
         ///
         /// Example:
@@ -3790,7 +3800,9 @@ pub enum Statement {
         ///  Triggering conditions
         condition: Option<Expr>,
         /// Execute logic block
-        exec_body: TriggerExecBody,
+        exec_body: Option<TriggerExecBody>,
+        /// For SQL dialects with statement(s) for a body
+        statements: Option<ConditionalStatements>,
         /// The characteristic of the trigger, which include whether the trigger is `DEFERRABLE`, `INITIALLY DEFERRED`, or `INITIALLY IMMEDIATE`,
         characteristics: Option<ConstraintCharacteristics>,
     },
@@ -4587,6 +4599,7 @@ impl fmt::Display for Statement {
             }
             Statement::CreateFunction(create_function) => create_function.fmt(f),
             Statement::CreateTrigger {
+                or_alter,
                 or_replace,
                 is_constraint,
                 name,
@@ -4599,19 +4612,30 @@ impl fmt::Display for Statement {
                 condition,
                 include_each,
                 exec_body,
+                statements,
                 characteristics,
             } => {
                 write!(
                     f,
-                    "CREATE {or_replace}{is_constraint}TRIGGER {name} {period}",
+                    "CREATE {or_alter}{or_replace}{is_constraint}TRIGGER {name} ",
+                    or_alter = if *or_alter { "OR ALTER " } else { "" },
                     or_replace = if *or_replace { "OR REPLACE " } else { "" },
                     is_constraint = if *is_constraint { "CONSTRAINT " } else { "" },
                 )?;
 
-                if !events.is_empty() {
-                    write!(f, " {}", display_separated(events, " OR "))?;
+                if exec_body.is_some() {
+                    write!(f, "{period}")?;
+                    if !events.is_empty() {
+                        write!(f, " {}", display_separated(events, " OR "))?;
+                    }
+                    write!(f, " ON {table_name}")?;
+                } else {
+                    write!(f, "ON {table_name}")?;
+                    write!(f, " {period}")?;
+                    if !events.is_empty() {
+                        write!(f, " {}", display_separated(events, ", "))?;
+                    }
                 }
-                write!(f, " ON {table_name}")?;
 
                 if let Some(referenced_table_name) = referenced_table_name {
                     write!(f, " FROM {referenced_table_name}")?;
@@ -4627,13 +4651,19 @@ impl fmt::Display for Statement {
 
                 if *include_each {
                     write!(f, " FOR EACH {trigger_object}")?;
-                } else {
+                } else if exec_body.is_some() {
                     write!(f, " FOR {trigger_object}")?;
                 }
                 if let Some(condition) = condition {
                     write!(f, " WHEN {condition}")?;
                 }
-                write!(f, " EXECUTE {exec_body}")
+                if let Some(exec_body) = exec_body {
+                    write!(f, " EXECUTE {exec_body}")?;
+                }
+                if let Some(statements) = statements {
+                    write!(f, " AS {statements}")?;
+                }
+                Ok(())
             }
             Statement::DropTrigger {
                 if_exists,

src/ast/trigger.rs

@@ -110,6 +110,7 @@ impl fmt::Display for TriggerEvent {
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
 pub enum TriggerPeriod {
+    For,
     After,
     Before,
     InsteadOf,
@@ -118,6 +119,7 @@ pub enum TriggerPeriod {
 impl fmt::Display for TriggerPeriod {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
+            TriggerPeriod::For => write!(f, "FOR"),
             TriggerPeriod::After => write!(f, "AFTER"),
             TriggerPeriod::Before => write!(f, "BEFORE"),
             TriggerPeriod::InsteadOf => write!(f, "INSTEAD OF"),

src/dialect/mssql.rs

@@ -18,6 +18,7 @@
 use crate::ast::helpers::attached_token::AttachedToken;
 use crate::ast::{
     BeginEndStatements, ConditionalStatementBlock, ConditionalStatements, IfStatement, Statement,
+    TriggerObject,
 };
 use crate::dialect::Dialect;
 use crate::keywords::{self, Keyword};
@@ -125,6 +126,15 @@ impl Dialect for MsSqlDialect {
     fn parse_statement(&self, parser: &mut Parser) -> Option<Result<Statement, ParserError>> {
         if parser.peek_keyword(Keyword::IF) {
             Some(self.parse_if_stmt(parser))
+        } else if parser.parse_keywords(&[Keyword::CREATE, Keyword::TRIGGER]) {
+            Some(self.parse_create_trigger(parser, false))
+        } else if parser.parse_keywords(&[
+            Keyword::CREATE,
+            Keyword::OR,
+            Keyword::ALTER,
+            Keyword::TRIGGER,
+        ]) {
+            Some(self.parse_create_trigger(parser, true))
         } else {
             None
         }
@@ -215,6 +225,42 @@ impl MsSqlDialect {
         }))
     }
 
+    /// Parse `CREATE TRIGGER` for [MsSql]
+    ///
+    /// [MsSql]: https://learn.microsoft.com/en-us/sql/t-sql/statements/create-trigger-transact-sql
+    fn parse_create_trigger(
+        &self,
+        parser: &mut Parser,
+        or_alter: bool,
+    ) -> Result<Statement, ParserError> {
+        let name = parser.parse_object_name(false)?;
+        parser.expect_keyword_is(Keyword::ON)?;
+        let table_name = parser.parse_object_name(false)?;
+        let period = parser.parse_trigger_period()?;
+        let events = parser.parse_comma_separated(Parser::parse_trigger_event)?;
+
+        parser.expect_keyword_is(Keyword::AS)?;
+        let statements = Some(parser.parse_conditional_statements(&[Keyword::END])?);
+
+        Ok(Statement::CreateTrigger {
+            or_alter,
+            or_replace: false,
+            is_constraint: false,
+            name,
+            period,
+            events,
+            table_name,
+            referenced_table_name: None,
+            referencing: Vec::new(),
+            trigger_object: TriggerObject::Statement,
+            include_each: false,
+            condition: None,
+            exec_body: None,
+            statements,
+            characteristics: None,
+        })
+    }
+
     /// Parse a sequence of statements, optionally separated by semicolon.
     ///
     /// Stops parsing when reaching EOF or the given keyword.

src/parser/mod.rs

@@ -745,26 +745,38 @@ impl<'a> Parser<'a> {
             }
         };
 
+        let conditional_statements = self.parse_conditional_statements(terminal_keywords)?;
+
+        Ok(ConditionalStatementBlock {
+            start_token: AttachedToken(start_token),
+            condition,
+            then_token,
+            conditional_statements,
+        })
+    }
+
+    /// Parse a BEGIN/END block or a sequence of statements
+    /// This could be inside of a conditional (IF, CASE, WHILE etc.) or an object body defined optionally BEGIN/END and one or more statements.
+    pub(crate) fn parse_conditional_statements(
+        &mut self,
+        terminal_keywords: &[Keyword],
+    ) -> Result<ConditionalStatements, ParserError> {
         let conditional_statements = if self.peek_keyword(Keyword::BEGIN) {
             let begin_token = self.expect_keyword(Keyword::BEGIN)?;
             let statements = self.parse_statement_list(terminal_keywords)?;
             let end_token = self.expect_keyword(Keyword::END)?;
+
             ConditionalStatements::BeginEnd(BeginEndStatements {
                 begin_token: AttachedToken(begin_token),
                 statements,
                 end_token: AttachedToken(end_token),
             })
         } else {
-            let statements = self.parse_statement_list(terminal_keywords)?;
-            ConditionalStatements::Sequence { statements }
+            ConditionalStatements::Sequence {
+                statements: self.parse_statement_list(terminal_keywords)?,
+            }
         };
-
-        Ok(ConditionalStatementBlock {
-            start_token: AttachedToken(start_token),
-            condition,
-            then_token,
-            conditional_statements,
-        })
+        Ok(conditional_statements)
     }
 
     /// Parse a `RAISE` statement.
@@ -4614,9 +4626,9 @@ impl<'a> Parser<'a> {
         } else if self.parse_keyword(Keyword::FUNCTION) {
             self.parse_create_function(or_alter, or_replace, temporary)
         } else if self.parse_keyword(Keyword::TRIGGER) {
-            self.parse_create_trigger(or_replace, false)
+            self.parse_create_trigger(or_alter, or_replace, false)
         } else if self.parse_keywords(&[Keyword::CONSTRAINT, Keyword::TRIGGER]) {
-            self.parse_create_trigger(or_replace, true)
+            self.parse_create_trigger(or_alter, or_replace, true)
         } else if self.parse_keyword(Keyword::MACRO) {
             self.parse_create_macro(or_replace, temporary)
         } else if self.parse_keyword(Keyword::SECRET) {
@@ -5314,10 +5326,11 @@ impl<'a> Parser<'a> {
 
     pub fn parse_create_trigger(
         &mut self,
+        or_alter: bool,
         or_replace: bool,
         is_constraint: bool,
     ) -> Result<Statement, ParserError> {
-        if !dialect_of!(self is PostgreSqlDialect | GenericDialect | MySqlDialect) {
+        if !dialect_of!(self is PostgreSqlDialect | GenericDialect | MySqlDialect | MsSqlDialect) {
             self.prev_token();
             return self.expected("an object type after CREATE", self.peek_token());
         }
@@ -5363,6 +5376,7 @@ impl<'a> Parser<'a> {
         let exec_body = self.parse_trigger_exec_body()?;
 
         Ok(Statement::CreateTrigger {
+            or_alter,
             or_replace,
             is_constraint,
             name,
@@ -5374,18 +5388,21 @@ impl<'a> Parser<'a> {
             trigger_object,
             include_each,
             condition,
-            exec_body,
+            exec_body: Some(exec_body),
+            statements: None,
             characteristics,
         })
     }
 
     pub fn parse_trigger_period(&mut self) -> Result<TriggerPeriod, ParserError> {
         Ok(
             match self.expect_one_of_keywords(&[
+                Keyword::FOR,
                 Keyword::BEFORE,
                 Keyword::AFTER,
                 Keyword::INSTEAD,
             ])? {
+                Keyword::FOR => TriggerPeriod::For,
                 Keyword::BEFORE => TriggerPeriod::Before,
                 Keyword::AFTER => TriggerPeriod::After,
                 Keyword::INSTEAD => self