#882 Implement to DatabaseMetaData.getSchemas return schemas

src/docs/asciidoc/release_notes.adoc

@@ -508,6 +508,21 @@ Artificial testing on local WiFi with small blobs (200 bytes) shows a 30,000-45,
 
 This optimization was backported to Jaybird 5.0.8 and Jaybird 6.0.2.
 
+[#schemas]
+=== Schema support
+
+Firebird 6.0 introduces schemas, and Jaybird 7 provides support for schemas as defined in the JDBC specification.
+
+Changes include:
+
+* `DatabaseMetaData`
+** `getSchemas()` returns all defined schemas
+** `getSchemas(String catalog, String schemaPattern)` returns all schemas matching the `LIKE` pattern `schemaPattern`, with the following caveats
+*** `catalog` non-empty will return no rows;
+we recommend to always use `null` for `catalog`.
+*** `schemaPattern` empty will return no rows (there are no schemas with an empty name);
+use `null` or `"%"` to match all schemas
+
 // TODO add major changes
 
 [#other-fixes-and-changes]

src/main/org/firebirdsql/jdbc/FBDatabaseMetaData.java

@@ -1263,6 +1263,11 @@ public ResultSet getSchemas() throws SQLException {
         return getSchemas(null, null);
     }
 
+    @Override
+    public ResultSet getSchemas(String catalog, String schemaPattern) throws SQLException {
+        return GetSchemas.create(getDbMetadataMediator()).getSchemas(catalog, schemaPattern);
+    }
+
     /**
      * {@inheritDoc}
      * <p>
@@ -1765,11 +1770,6 @@ public ResultSet getFunctions(String catalog, String schemaPattern, String funct
         return GetFunctions.create(getDbMetadataMediator()).getFunctions(catalog, functionNamePattern);
     }
 
-    @Override
-    public ResultSet getSchemas(String catalog, String schemaPattern) throws SQLException {
-        return GetSchemas.create(getDbMetadataMediator()).getSchemas();
-    }
-
     @Override
     public boolean isWrapperFor(Class<?> iface) throws SQLException {
         return iface != null && iface.isAssignableFrom(FBDatabaseMetaData.class);

src/main/org/firebirdsql/jdbc/metadata/GetSchemas.java

@@ -4,13 +4,14 @@
 package org.firebirdsql.jdbc.metadata;
 
 import org.firebirdsql.gds.ng.fields.RowDescriptor;
+import org.firebirdsql.gds.ng.fields.RowValue;
 import org.firebirdsql.jdbc.DbMetadataMediator;
-import org.firebirdsql.jdbc.FBResultSet;
+import org.firebirdsql.jdbc.DbMetadataMediator.MetadataQuery;
+import org.firebirdsql.util.FirebirdSupportInfo;
 
 import java.sql.ResultSet;
 import java.sql.SQLException;
 
-import static java.util.Collections.emptyList;
 import static org.firebirdsql.gds.ISCConstants.SQL_VARYING;
 import static org.firebirdsql.jdbc.metadata.FbMetadataConstants.OBJECT_NAME_LENGTH;
 
@@ -20,23 +21,100 @@
  * @author Mark Rotteveel
  * @since 5
  */
-public final class GetSchemas {
+public abstract class GetSchemas extends AbstractMetadataMethod {
 
     private static final RowDescriptor ROW_DESCRIPTOR = DbMetadataMediator.newRowDescriptorBuilder(2)
             .at(0).simple(SQL_VARYING, OBJECT_NAME_LENGTH, "TABLE_SCHEM", "TABLESCHEMAS").addField()
             .at(1).simple(SQL_VARYING, OBJECT_NAME_LENGTH, "TABLE_CATALOG", "TABLESCHEMAS").addField()
             .toRowDescriptor();
 
-    private GetSchemas() {
+    private GetSchemas(DbMetadataMediator mediator) {
+        super(ROW_DESCRIPTOR, mediator);
     }
 
-    public ResultSet getSchemas() throws SQLException {
-        return new FBResultSet(ROW_DESCRIPTOR, emptyList());
+    public ResultSet getSchemas(String catalog, String schemaPattern) throws SQLException {
+        if (!(catalog == null || catalog.isEmpty()) || "".equals(schemaPattern)) {
+            // matching schema name not possible
+            return createEmpty();
+        }
+        MetadataQuery metadataQuery = createGetSchemasQuery(schemaPattern);
+        return createMetaDataResultSet(metadataQuery);
     }
 
+    @Override
+    final RowValue createMetadataRow(ResultSet rs, RowValueBuilder valueBuilder) throws SQLException {
+        return valueBuilder
+                .at(0).setString(rs.getString("TABLE_SCHEM"))
+                .toRowValue(true);
+    }
+
+    abstract MetadataQuery createGetSchemasQuery(String schemaPattern);
+
     @SuppressWarnings("unused")
     public static GetSchemas create(DbMetadataMediator mediator) {
-        return new GetSchemas();
+        FirebirdSupportInfo firebirdSupportInfo = mediator.getFirebirdSupportInfo();
+        // NOTE: Indirection through static method prevents unnecessary classloading
+        if (firebirdSupportInfo.isVersionEqualOrAbove(6)) {
+            return FB6.createInstance(mediator);
+        } else {
+            return FB5.createInstance(mediator);
+        }
+    }
+
+    /**
+     * Implementation for Firebird 5.0 and older.
+     */
+    private static final class FB5 extends GetSchemas {
+
+        private FB5(DbMetadataMediator mediator) {
+            super(mediator);
+        }
+
+        private static GetSchemas createInstance(DbMetadataMediator mediator) {
+            return new FB5(mediator);
+        }
+
+        @Override
+        public ResultSet getSchemas(String catalog, String schemaPattern) throws SQLException {
+            return createEmpty();
+        }
+
+        @Override
+        MetadataQuery createGetSchemasQuery(String schemaPattern) {
+            throw new UnsupportedOperationException("This method should not get called for Firebird 5.0 and older");
+        }
+
+    }
+
+    /**
+     * Implementation for Firebird 6.0 and higher.
+     */
+    private static final class FB6 extends GetSchemas {
+
+        private static final String GET_SCHEMAS_FRAGMENT_6 = """
+                select RDB$SCHEMA_NAME as TABLE_SCHEM
+                from "SYSTEM".RDB$SCHEMAS
+                """;
+
+        private static final String GET_SCHEMAS_ORDER_BY_6 = "\norder by RDB$SCHEMA_NAME";
+
+        private FB6(DbMetadataMediator mediator) {
+            super(mediator);
+        }
+
+        private static GetSchemas createInstance(DbMetadataMediator mediator) {
+            return new FB6(mediator);
+        }
+
+        @Override
+        MetadataQuery createGetSchemasQuery(String schemaPattern) {
+            var schemaClause = new Clause("RDB$SCHEMA_NAME", schemaPattern);
+            String sql = GET_SCHEMAS_FRAGMENT_6
+                    + (schemaClause.hasCondition() ? "\nwhere " + schemaClause.getCondition(false) : "")
+                    + GET_SCHEMAS_ORDER_BY_6;
+            return new MetadataQuery(sql, Clause.parameters(schemaClause));
+        }
+
     }
 
 }

src/test/org/firebirdsql/common/extension/UsesDatabaseExtension.java

@@ -11,9 +11,10 @@
 import org.junit.jupiter.api.extension.ExtensionContext;
 
 import java.sql.SQLException;
-import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 import static java.util.Collections.emptyList;
 import static org.firebirdsql.common.FBTestProperties.createFBManager;
@@ -40,7 +41,7 @@ public abstract class UsesDatabaseExtension {
     private final boolean initialCreate;
     private FBManager fbManager = null;
     private final List<String> initStatements;
-    private final List<String> databasesToDrop = new ArrayList<>();
+    private final Set<String> databasesToDrop = new HashSet<>();
 
     private UsesDatabaseExtension(boolean initialCreate) {
         this(initialCreate, emptyList());
@@ -72,6 +73,7 @@ void sharedAfter() {
         } catch (Exception e){
             System.getLogger(getClass().getName()).log(System.Logger.Level.ERROR, "Exception dropping DBs", e);
         } finally {
+            databasesToDrop.clear();
             try {
                 if (!(fbManager == null || fbManager.getState().equals("Stopped"))) {
                     fbManager.stop();