feat: model PostgreSQL table inheritance references (#2692)

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

Author: minleejae

src/main/java/net/sf/jsqlparser/statement/create/table/CreateTable.java

@@ -38,6 +38,7 @@ public class CreateTable implements Statement {
     private DuplicateHandling duplicateHandling;
     private Table likeTable;
     private Table cloneTable;
+    private List<Table> inherits;
     private ColDataType ofType;
     private boolean selectParenthesis;
     private boolean useAsKeyword = true;
@@ -347,6 +348,27 @@ public void setPartitionBound(PartitionBound partitionBound) {
         this.partitionBound = partitionBound;
     }
 
+    /** PostgreSQL parent tables, in declaration order; null if INHERITS is absent. */
+    public List<Table> getInherits() {
+        return inherits;
+    }
+
+    public void setInherits(List<Table> inherits) {
+        this.inherits = inherits;
+    }
+
+    public CreateTable withInherits(List<Table> inherits) {
+        setInherits(inherits);
+        return this;
+    }
+
+    /** Shared rendering of the structured parent references. */
+    public void appendInheritanceTo(StringBuilder builder) {
+        if (inherits != null) {
+            builder.append(" INHERITS ").append(PlainSelect.getStringList(inherits, true, true));
+        }
+    }
+
     public boolean isSelectParenthesis() {
         return selectParenthesis;
     }
@@ -369,6 +391,7 @@ public String toString() {
         StringBuilder b = new StringBuilder();
         appendCreateClause(b);
         appendColumnDefinitions(b);
+        appendInheritanceTo(b);
         if (partitionBound != null) {
             b.append(" ").append(partitionBound);
         }

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

@@ -109,6 +109,9 @@ public static void visit(CreateTable table, Consumer<Expression> expressions,
                 }
             });
         }
+        if (table.getInherits() != null) {
+            table.getInherits().forEach(parent -> accept(parent, tables));
+        }
         accept(table.getTrailingLikeTable(), tables);
         accept(table.getPartitionOf(), tables);
         visit(table.getPartitioning(), expressions);

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

@@ -106,6 +106,7 @@ public void deParse(CreateTable createTable) {
             builder.append(")");
         }
 
+        createTable.appendInheritanceTo(builder);
         if (createTable.getPartitionBound() != null) {
             builder.append(' ');
             createTable.getPartitionBound().appendTo(builder,

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

@@ -15054,6 +15054,8 @@ CreateTable CreateTable(boolean isUsingOrReplace):
     Table partitionOfTable = null;
     PartitionBound partitionBound = null;
     ColDataType ofType = null;
+    Table parent;
+    List<Table> parents = new ArrayList<Table>();
     boolean withData;
 }
 {
@@ -15078,6 +15080,8 @@ CreateTable CreateTable(boolean isUsingOrReplace):
     [ LOOKAHEAD(2) <K_PARTITION> <K_OF> partitionOfTable=Table()
         { createTable.setPartitionOf(partitionOfTable); } ]
     [ LOOKAHEAD(2) (
+        LOOKAHEAD("(" ")") "(" ")" { createTable.setTableElements(tableElements); }
+        |
         LOOKAHEAD(3) (
             "(" tableColumn=RelObjectName() { columns.add(tableColumn); } ("," tableColumn=RelObjectName() { columns.add(tableColumn); } )* ")"
         )
@@ -15094,6 +15098,10 @@ CreateTable CreateTable(boolean isUsingOrReplace):
             )
         )
     ]
+    [ LOOKAHEAD({ isKeywordAhead("INHERITS") }) ContextualKeyword("INHERITS")
+        "(" parent=Table() { parents.add(parent); }
+        ( "," parent=Table() { parents.add(parent); } )* ")"
+        { createTable.setInherits(parents); } ]
     [ LOOKAHEAD({ partitionOfTable != null })
         partitionBound=PostgreSqlPartitionBound()
         { createTable.setPartitionBound(partitionBound); } ]

src/test/java/net/sf/jsqlparser/statement/create/PostgreSqlTableInheritanceTest.java

@@ -0,0 +1,78 @@
+/*-
+ * #%L
+ * JSQLParser library
+ * %%
+ * Copyright (C) 2004 - 2019 JSQLParser
+ * %%
+ * Dual licensed under GNU LGPL 2.1 or Apache License 2.0
+ * #L%
+ */
+package net.sf.jsqlparser.statement.create;
+
+import static org.junit.jupiter.api.Assertions.*;
+import java.util.ArrayList;
+import java.util.List;
+import net.sf.jsqlparser.JSQLParserException;
+import net.sf.jsqlparser.parser.CCJSqlParserUtil;
+import net.sf.jsqlparser.schema.Table;
+import net.sf.jsqlparser.statement.create.table.CreateTable;
+import net.sf.jsqlparser.util.TableDefinitionTraversal;
+import net.sf.jsqlparser.util.TablesNamesFinder;
+import net.sf.jsqlparser.util.deparser.StatementDeParser;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+class PostgreSqlTableInheritanceTest {
+    @ParameterizedTest
+    @ValueSource(strings = {"parent", "public.parent", "public.parent, other.parent2",
+            "\"Odd.Schema\".\"Parent.Name\""})
+    void modelsAndVisitsParentTables(String parents) throws JSQLParserException {
+        for (String definition : new String[] {"()", "(extra INT)", "(LIKE source, extra INT)"}) {
+            CreateTable table = (CreateTable) CCJSqlParserUtil.parse(
+                    "CREATE TABLE child " + definition + " INHERITS (" + parents
+                            + ") WITH (fillfactor = 80)");
+            List<Table> inherited = table.getInherits();
+            assertEquals(parents.split(", ").length, inherited.size());
+            assertEquals(parents.split(", ")[0], inherited.get(0).getFullyQualifiedName());
+            List<Table> visited = new ArrayList<>();
+            TableDefinitionTraversal.visit(table, e -> {
+            }, visited::add);
+            for (Table parent : inherited) {
+                assertTrue(visited.stream().anyMatch(t -> t == parent));
+                assertTrue(new TablesNamesFinder().getTables(table)
+                        .contains(parent.getFullyQualifiedName()));
+            }
+            roundTrip(table);
+            inherited.set(0, new Table("replacement"));
+            assertTrue(table.toString().contains("INHERITS (replacement"));
+            roundTrip(table);
+        }
+    }
+
+    @Test
+    void preservesEmptyDefinitionsAndCanRemoveInheritance() throws JSQLParserException {
+        CreateTable table =
+                (CreateTable) CCJSqlParserUtil.parse("CREATE TABLE child () INHERITS (parent)");
+        assertNotNull(table.getTableElements());
+        assertTrue(table.getTableElements().isEmpty());
+        table.setInherits(null);
+        assertEquals("CREATE TABLE child ()", table.toString());
+        roundTrip(table);
+        assertEquals(2, CCJSqlParserUtil.parseStatements(table + "; SELECT 1").size());
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {"()", "(parent,)", "(parent AS p)", "(parent + 1)"})
+    void rejectsMalformedParentLists(String parents) {
+        assertThrows(JSQLParserException.class,
+                () -> CCJSqlParserUtil.parse("CREATE TABLE child () INHERITS " + parents));
+    }
+
+    private static void roundTrip(CreateTable table) throws JSQLParserException {
+        StringBuilder out = new StringBuilder();
+        table.accept(new StatementDeParser(out));
+        assertEquals(table.toString(), out.toString());
+        assertEquals(out.toString(), CCJSqlParserUtil.parse(out.toString()).toString());
+    }
+}