feat: support PostgreSQL ALTER SCHEMA actions

Signed-off-by: minleejae <mmj9808@gmail.com>

Author: minleejae

src/main/java/net/sf/jsqlparser/parser/feature/Feature.java

@@ -507,6 +507,8 @@ public enum Feature {
      * @see CreateSchema
      */
     createSchema,
+    /** SQL ALTER SCHEMA rename and owner changes. */
+    alterSchema,
     /**
      * SQL "CREATE VIEW" statement is allowed
      *

src/main/java/net/sf/jsqlparser/statement/StatementVisitor.java

@@ -9,6 +9,7 @@
  */
 package net.sf.jsqlparser.statement;
 
+import net.sf.jsqlparser.statement.alter.schema.AlterSchema;
 import net.sf.jsqlparser.statement.oracle.OracleBlock;
 import net.sf.jsqlparser.statement.oracle.OracleAssignment;
 import net.sf.jsqlparser.statement.oracle.OracleNullStatement;
@@ -534,6 +535,14 @@ default void visit(CreateRole statement) {
         visit(statement, null);
     }
 
+    default <S> T visit(AlterSchema statement, S context) {
+        return null;
+    }
+
+    default void visit(AlterSchema statement) {
+        visit(statement, null);
+    }
+
     default <S> T visit(AlterRole statement, S context) {
         return null;
     }

src/main/java/net/sf/jsqlparser/statement/alter/schema/AlterSchema.java

@@ -0,0 +1,79 @@
+/*-
+ * #%L
+ * JSQLParser library
+ * %%
+ * Copyright (C) 2004 - 2026 JSQLParser
+ * %%
+ * Dual licensed under GNU LGPL 2.1 or Apache License 2.0
+ * #L%
+ */
+package net.sf.jsqlparser.statement.alter.schema;
+
+import net.sf.jsqlparser.statement.Statement;
+import net.sf.jsqlparser.statement.StatementVisitor;
+
+/** PostgreSQL schema name or ownership change. Names retain SQL identifier quoting. */
+public class AlterSchema implements Statement {
+    public enum Action {
+        RENAME, OWNER
+    }
+
+    private String schemaName;
+    private Action action;
+    private String newName;
+    private String owner;
+
+    public String getSchemaName() {
+        return schemaName;
+    }
+
+    public void setSchemaName(String schemaName) {
+        this.schemaName = schemaName;
+    }
+
+    public Action getAction() {
+        return action;
+    }
+
+    public void setAction(Action action) {
+        this.action = action;
+    }
+
+    public String getNewName() {
+        return newName;
+    }
+
+    public void setNewName(String newName) {
+        this.newName = newName;
+    }
+
+    public String getOwner() {
+        return owner;
+    }
+
+    public void setOwner(String owner) {
+        this.owner = owner;
+    }
+
+    public StringBuilder appendTo(StringBuilder builder) {
+        builder.append("ALTER SCHEMA ").append(schemaName);
+        if (action == Action.RENAME) {
+            builder.append(" RENAME TO ").append(newName);
+        } else if (action == Action.OWNER) {
+            builder.append(" OWNER TO ").append(owner);
+        } else {
+            throw new IllegalStateException("Expected a schema alteration action");
+        }
+        return builder;
+    }
+
+    @Override
+    public String toString() {
+        return appendTo(new StringBuilder()).toString();
+    }
+
+    @Override
+    public <T, S> T accept(StatementVisitor<T> visitor, S context) {
+        return visitor.visit(this, context);
+    }
+}

src/main/java/net/sf/jsqlparser/util/TablesNamesFinder.java

@@ -9,6 +9,7 @@
  */
 package net.sf.jsqlparser.util;
 
+import net.sf.jsqlparser.statement.alter.schema.AlterSchema;
 import net.sf.jsqlparser.statement.select.MatchRecognize;
 import net.sf.jsqlparser.expression.RowPatternFunction;
 
@@ -2783,6 +2784,12 @@ public <S> Void visit(CreateRole statement, S context) {
         return null;
     }
 
+    @Override
+    public <S> Void visit(AlterSchema statement, S context) {
+        // Schema and owner names do not refer to tables.
+        return null;
+    }
+
     @Override
     public <S> Void visit(AlterRole statement, S context) {
         return null;

src/main/java/net/sf/jsqlparser/util/deparser/StatementDeParser.java

@@ -9,6 +9,7 @@
  */
 package net.sf.jsqlparser.util.deparser;
 
+import net.sf.jsqlparser.statement.alter.schema.AlterSchema;
 import net.sf.jsqlparser.statement.oracle.OracleBlock;
 import net.sf.jsqlparser.statement.oracle.OracleAssignment;
 import net.sf.jsqlparser.statement.oracle.OracleNullStatement;
@@ -708,6 +709,11 @@ public <S> StringBuilder visit(CreateRole statement, S context) {
         return builder;
     }
 
+    @Override
+    public <S> StringBuilder visit(AlterSchema statement, S context) {
+        return statement.appendTo(builder);
+    }
+
     @Override
     public <S> StringBuilder visit(AlterRole statement, S context) {
         statement.appendTo(builder, e -> e.accept(expressionDeParser, context));

src/main/java/net/sf/jsqlparser/util/validation/feature/FeaturesAllowed.java

@@ -113,7 +113,7 @@ public class FeaturesAllowed implements FeatureSetValidation, ModifyableFeatureS
      */
     public static final FeaturesAllowed ALTER =
             new FeaturesAllowed("ALTER", Feature.alterTable, Feature.alterSequence,
-                    Feature.alterView, Feature.alterIndex)
+                    Feature.alterView, Feature.alterIndex, Feature.alterSchema)
                     .unmodifyable();
     /**
      * all "DROP" {@link Feature}'s

src/main/java/net/sf/jsqlparser/util/validation/feature/PostgresqlVersion.java

@@ -103,7 +103,7 @@ public enum PostgresqlVersion implements Version {
                     Feature.createDomain, Feature.alterDomain,
                     Feature.createExtension, Feature.alterExtension, // https://www.postgresql.org/docs/current/sql-altersequence.html
                     Feature.alterSequence, // https://www.postgresql.org/docs/current/sql-createschema.html
-                    Feature.createSchema, // https://www.postgresql.org/docs/current/sql-createindex.html
+                    Feature.createSchema, Feature.alterSchema, // https://www.postgresql.org/docs/current/sql-createindex.html
                     Feature.createIndex, // https://www.postgresql.org/docs/current/sql-createtable.html
                     Feature.createTable, Feature.createTableUnlogged,
                     Feature.createTableCreateOptionStrings, Feature.createTableTableOptionStrings,

src/main/java/net/sf/jsqlparser/util/validation/validator/StatementValidator.java

@@ -9,6 +9,7 @@
  */
 package net.sf.jsqlparser.util.validation.validator;
 
+import net.sf.jsqlparser.statement.alter.schema.AlterSchema;
 import net.sf.jsqlparser.statement.oracle.OracleBlock;
 import net.sf.jsqlparser.statement.oracle.OracleAssignment;
 import net.sf.jsqlparser.statement.oracle.OracleNullStatement;
@@ -882,6 +883,12 @@ public <S> Void visit(CreateRole statement, S context) {
         return null;
     }
 
+    @Override
+    public <S> Void visit(AlterSchema statement, S context) {
+        validateFeature(Feature.alterSchema);
+        return null;
+    }
+
     @Override
     public <S> Void visit(AlterRole statement, S context) {
         validateFeature(Feature.alterRole);

src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt

@@ -49,6 +49,7 @@ import net.sf.jsqlparser.schema.*;
 import net.sf.jsqlparser.statement.*;
 import net.sf.jsqlparser.statement.analyze.*;
 import net.sf.jsqlparser.statement.alter.*;
+import net.sf.jsqlparser.statement.alter.schema.AlterSchema;
 import net.sf.jsqlparser.statement.alter.sequence.*;
 import net.sf.jsqlparser.statement.comment.*;
 import net.sf.jsqlparser.statement.create.database.*;
@@ -17656,6 +17657,8 @@ Statement Alter():
                 |
                 statement = AlterDefaultPrivileges()
                 |
+                LOOKAHEAD(<K_SCHEMA>) statement = AlterSchema()
+                |
                 LOOKAHEAD(<K_TYPE>) statement = AlterType()
                 |
                 LOOKAHEAD(<K_DOMAIN>) statement = AlterDomain()
@@ -18095,6 +18098,23 @@ CreateRole CreateRole():
     { requireAccessSyntax(!role.isUseWith() || !role.getOptions().isEmpty(), "WITH requires role attributes"); return role; }
 }
 
+AlterSchema AlterSchema():
+{
+    AlterSchema statement = new AlterSchema();
+    String name;
+}
+{
+    <K_SCHEMA> name=RelObjectName() { statement.setSchemaName(name); }
+    (
+        <K_RENAME> <K_TO> name=RelObjectName()
+        { statement.setAction(AlterSchema.Action.RENAME); statement.setNewName(name); }
+        |
+        ContextualKeyword("OWNER") <K_TO> name=RelObjectName()
+        { statement.setAction(AlterSchema.Action.OWNER); statement.setOwner(name); }
+    )
+    { return statement; }
+}
+
 AlterRole AlterRole():
 {
     AlterRole role = new AlterRole(); String name; RoleOption option; Token token; Expression value;

src/test/java/net/sf/jsqlparser/statement/alter/AlterSchemaTest.java

@@ -0,0 +1,98 @@
+/*-
+ * #%L
+ * JSQLParser library
+ * %%
+ * Copyright (C) 2004 - 2026 JSQLParser
+ * %%
+ * Dual licensed under GNU LGPL 2.1 or Apache License 2.0
+ * #L%
+ */
+package net.sf.jsqlparser.statement.alter;
+
+import static org.junit.jupiter.api.Assertions.*;
+import java.util.List;
+import net.sf.jsqlparser.JSQLParserException;
+import net.sf.jsqlparser.parser.AbstractJSqlParser.Dialect;
+import net.sf.jsqlparser.parser.CCJSqlParserUtil;
+import net.sf.jsqlparser.parser.feature.Feature;
+import net.sf.jsqlparser.statement.StatementVisitorAdapter;
+import net.sf.jsqlparser.statement.Statements;
+import net.sf.jsqlparser.statement.alter.schema.AlterSchema;
+import net.sf.jsqlparser.util.TablesNamesFinder;
+import net.sf.jsqlparser.util.deparser.StatementDeParser;
+import net.sf.jsqlparser.util.validation.Validation;
+import net.sf.jsqlparser.util.validation.feature.FeaturesAllowed;
+import net.sf.jsqlparser.util.validation.feature.PostgresqlVersion;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+class AlterSchemaTest {
+    @ParameterizedTest
+    @ValueSource(strings = {"ALTER SCHEMA analytics RENAME TO reporting",
+            "ALTER SCHEMA \"a.b\" RENAME TO \"next.schema\"",
+            "ALTER SCHEMA s OWNER TO app", "ALTER SCHEMA s OWNER TO CURRENT_USER",
+            "ALTER SCHEMA s OWNER TO CURRENT_ROLE", "ALTER SCHEMA s OWNER TO SESSION_USER",
+            "ALTER SCHEMA \"Case\" OWNER TO \"role.with.dot\""})
+    void parsesAndRendersSchemaActions(String sql) throws Exception {
+        AlterSchema schema = parse(sql);
+        assertEquals(sql, schema.toString());
+        assertTrue(new TablesNamesFinder().getTables(schema).isEmpty());
+        roundTrip(schema);
+        assertTrue(new Validation(List.of(PostgresqlVersion.V14), sql).validate().isEmpty());
+    }
+
+    @Test
+    void supportsAstMutationAndVisitorDispatch() throws Exception {
+        AlterSchema schema = parse("ALTER SCHEMA s RENAME TO renamed");
+        assertEquals(AlterSchema.Action.RENAME, schema.getAction());
+        assertEquals("renamed", schema.getNewName());
+        schema.setSchemaName("\"schema.name\"");
+        schema.setNewName("replacement");
+        roundTrip(schema);
+        schema.setAction(AlterSchema.Action.OWNER);
+        schema.setOwner("CURRENT_ROLE");
+        assertEquals("ALTER SCHEMA \"schema.name\" OWNER TO CURRENT_ROLE", schema.toString());
+        roundTrip(schema);
+        Object context = new Object();
+        assertEquals("visited", schema.accept(new StatementVisitorAdapter<String>() {
+            @Override
+            public <S> String visit(AlterSchema statement, S supplied) {
+                assertSame(schema, statement);
+                assertSame(context, supplied);
+                return "visited";
+            }
+        }, context));
+    }
+
+    @Test
+    void respectsStatementBoundariesAndValidationCapabilities() throws Exception {
+        Statements statements = CCJSqlParserUtil.parseStatements(
+                "ALTER SCHEMA s OWNER TO CURRENT_USER; SELECT 1;");
+        assertEquals(2, statements.size());
+        assertInstanceOf(AlterSchema.class, statements.get(0));
+        assertFalse(new Validation(List.of(FeaturesAllowed.SELECT),
+                "ALTER SCHEMA s RENAME TO r").validate().isEmpty());
+        assertTrue(new Validation(List.of(new FeaturesAllowed().add(Feature.alterSchema)),
+                "ALTER SCHEMA s RENAME TO r").validate().isEmpty());
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {"ALTER SCHEMA s RENAME", "ALTER SCHEMA s OWNER TO",
+            "ALTER SCHEMA s RENAME TO 'not an identifier'", "ALTER SCHEMA s OWNER TO a.b",
+            "ALTER SCHEMA s OWNER TO a, b", "ALTER SCHEMA a.b RENAME TO c"})
+    void rejectsIncompleteActionsAndQualifiedSchemaOrRoleNames(String sql) {
+        assertThrows(JSQLParserException.class, () -> parse(sql));
+    }
+
+    private static AlterSchema parse(String sql) throws JSQLParserException {
+        return (AlterSchema) CCJSqlParserUtil.parse(sql, p -> p.withDialect(Dialect.POSTGRESQL));
+    }
+
+    private static void roundTrip(AlterSchema schema) throws Exception {
+        StringBuilder out = new StringBuilder();
+        schema.accept(new StatementDeParser(out), null);
+        assertEquals(schema.toString(), out.toString());
+        assertEquals(schema.toString(), parse(out.toString()).toString());
+    }
+}