feat: allow CATALOG in CREATE SCHEMA and DROP SCHEMA (h2database#4277)

* feat: allow `CATALOG` in `CREATE SCHEMA` and `DROP SCHEMA`

- fixes h2database#4276

* feat: allow `CATALOG` in `CREATE SCHEMA` and `DROP SCHEMA`

- do not document the optional `catalogName` because actual support is limited

* feat: allow `CATALOG` in `CREATE SCHEMA` and `DROP SCHEMA`

- do not carry the `catalogName` along

* feat: allow `CATALOG` in `CREATE SCHEMA` and `DROP SCHEMA`

- add tests for invalid `catalog` names

* feat: allow `CATALOG` in `CREATE SCHEMA` and `DROP SCHEMA`

- verify catalog name and encapsulate the logic

* feat: allow `CATALOG` in `CREATE SCHEMA` and `DROP SCHEMA`

- do not carry the catalog name along

* feat: allow `CATALOG` in `CREATE SCHEMA` and `DROP SCHEMA`

- minor style recommendations

Author: manticore-projects

h2/src/main/org/h2/command/Parser.java

@@ -2193,7 +2193,7 @@ private Prepared parseDrop() {
         } else if (readIf("SCHEMA")) {
             boolean ifExists = readIfExists(false);
             DropSchema command = new DropSchema(session);
-            command.setSchemaName(readIdentifier());
+            command.setSchemaName(readIdentifierWithCatalog());
             ifExists = readIfExists(ifExists);
             command.setIfExists(ifExists);
             ConstraintActionType dropAction = parseCascadeOrRestrict();
@@ -5532,6 +5532,31 @@ private String readIdentifierWithSchema() {
         return readIdentifierWithSchema(session.getCurrentSchemaName());
     }
 
+    /**
+     * <p>Reads the schema name with or without a catalog name.</p>
+     * <p>Merely for SQL:2016 compatibility.</p>
+     * <p>Since H2 does not support multiple catalogs:</p>
+     * <ul>
+     * <li>we verify against current catalog name and throw an exception when
+     * not matching</li>
+     * <li>we are going to ignore the catalog name because it is not needed
+     * anywhere</li>
+     * </ul>
+     *
+     * @return the SCHEMA name only (without the catalog name)
+     */
+    private String readIdentifierWithCatalog() {
+        String name = readIdentifier();
+        if (readIf(DOT)) {
+            if (equalsToken(name, database.getShortName()) || database.getIgnoreCatalogs()) {
+                name = readIdentifier();
+            } else {
+                throw DbException.get(ErrorCode.INVALID_NAME_1, name);
+            }
+        }
+        return name;
+    }
+
     private String readIdentifier() {
         if (!isIdentifier()) {
             /*
@@ -6708,7 +6733,7 @@ private CreateSchema parseCreateSchema() {
             command.setSchemaName(authorization);
             command.setAuthorization(authorization);
         } else {
-            command.setSchemaName(readIdentifier());
+            command.setSchemaName(readIdentifierWithCatalog());
             if (readIf(AUTHORIZATION)) {
                 authorization = readIdentifier();
             } else {

h2/src/test/org/h2/test/scripts/ddl/createSchema.sql

@@ -15,9 +15,17 @@ CREATE SCHEMA S1;
 CREATE SCHEMA S2 AUTHORIZATION TEST_USER;
 > ok
 
-CREATE SCHEMA S3 AUTHORIZATION TEST_ROLE;
+CREATE SCHEMA SCRIPT.S3 AUTHORIZATION TEST_ROLE;
 > ok
 
+-- invalid catalog name shall fail
+CREATE SCHEMA 1.S3 AUTHORIZATION TEST_ROLE;
+> exception SYNTAX_ERROR_2
+
+-- valid catalog name, but shall fail since we do not support multiple catalogs
+CREATE SCHEMA UNNAMED.S3 AUTHORIZATION TEST_ROLE;
+> exception INVALID_NAME_1
+
 CREATE SCHEMA AUTHORIZATION TEST_USER;
 > ok
 
@@ -42,7 +50,7 @@ DROP SCHEMA S1;
 DROP SCHEMA S2;
 > ok
 
-DROP SCHEMA S3;
+DROP SCHEMA SCRIPT.S3;
 > ok
 
 DROP USER TEST_USER;