Added support for system views when fetching tables etc from metadata

[siggemannen]

Changing DuckDBDatabaseMetaData so it supports viewing system views like information_schema

[staticlibs]

Thanks for the PR! Looks good to me.

To pass the formatter plrease run:

python3 -m pip install --user clang_format==11.0.1
make format

Or, alternatively, apply the following diff:

diff --git a/src/main/java/org/duckdb/DuckDBDatabaseMetaData.java b/src/main/java/org/duckdb/DuckDBDatabaseMetaData.java
index 9a48b14a8..e6387b004 100644
--- a/src/main/java/org/duckdb/DuckDBDatabaseMetaData.java
+++ b/src/main/java/org/duckdb/DuckDBDatabaseMetaData.java
@@ -722,7 +722,7 @@ public class DuckDBDatabaseMetaData implements DatabaseMetaData {
 
     @Override
     public ResultSet getTableTypes() throws SQLException {
-        String[] tableTypesArray = new String[] {"TABLE", "LOCAL TEMPORARY", "VIEW", "SYSTEM VIEW" };
+        String[] tableTypesArray = new String[] {"TABLE", "LOCAL TEMPORARY", "VIEW", "SYSTEM VIEW"};
         StringBuilder stringBuilder = new StringBuilder(128);
         boolean first = true;
         for (String tableType : tableTypesArray) {
@@ -759,15 +759,13 @@ public class DuckDBDatabaseMetaData implements DatabaseMetaData {
         sb.append("NULL::VARCHAR AS 'TYPE_NAME'").append(TRAILING_COMMA).append(lineSeparator());
         sb.append("NULL::VARCHAR AS 'SELF_REFERENCING_COL_NAME'").append(TRAILING_COMMA).append(lineSeparator());
         sb.append("NULL::VARCHAR AS 'REF_GENERATION'").append(TRAILING_COMMA).append(lineSeparator());
-        sb
-        .append(
-        "FROM (select database_name as table_catalog, schema_name as table_schema, table_name, CASE  WHEN (\"temporary\") THEN ('LOCAL TEMPORARY')  WHEN (\"internal\") THEN 'SYSTEM TABLE' ELSE 'TABLE' END AS table_type, comment AS TABLE_COMMENT")
-        .append(lineSeparator());
+        sb.append(
+              "FROM (select database_name as table_catalog, schema_name as table_schema, table_name, CASE  WHEN (\"temporary\") THEN ('LOCAL TEMPORARY')  WHEN (\"internal\") THEN 'SYSTEM TABLE' ELSE 'TABLE' END AS table_type, comment AS TABLE_COMMENT")
+            .append(lineSeparator());
         sb.append("from  duckdb_tables() x").append(lineSeparator());
-        sb
-        .append(
-        "union all select database_name,schema_name, view_name, CASE  WHEN (\"internal\") then 'SYSTEM VIEW' ELSE 'VIEW' END, comment from duckdb_views() x   ) x")
-        .append(lineSeparator());
+        sb.append(
+              "union all select database_name,schema_name, view_name, CASE  WHEN (\"internal\") then 'SYSTEM VIEW' ELSE 'VIEW' END, comment from duckdb_views() x   ) x")
+            .append(lineSeparator());
         sb.append("WHERE table_name LIKE ? ESCAPE '\\'").append(lineSeparator());
         boolean hasCatalogParam = appendEqualsQual(sb, "table_catalog", catalog);
         boolean hasSchemaParam = appendLikeQual(sb, "table_schema", schemaPattern);
@@ -820,15 +818,17 @@ public class DuckDBDatabaseMetaData implements DatabaseMetaData {
         sb.append("schema_name AS 'TABLE_SCHEM'").append(TRAILING_COMMA).append(lineSeparator());
         sb.append("table_name AS 'TABLE_NAME'").append(TRAILING_COMMA).append(lineSeparator());
         sb.append("column_name as 'COLUMN_NAME'").append(TRAILING_COMMA).append(lineSeparator());
-        sb.append(makeDataMap("regexp_replace(c.data_type, '\\(.*\\)', '')", "DATA_TYPE")).append(TRAILING_COMMA)
-        .append(lineSeparator());
+        sb.append(makeDataMap("regexp_replace(c.data_type, '\\(.*\\)', '')", "DATA_TYPE"))
+            .append(TRAILING_COMMA)
+            .append(lineSeparator());
         sb.append("c.data_type AS 'TYPE_NAME'").append(TRAILING_COMMA).append(lineSeparator());
         sb.append("numeric_precision AS 'COLUMN_SIZE'").append(TRAILING_COMMA).append(lineSeparator());
         sb.append("NULL AS 'BUFFER_LENGTH'").append(TRAILING_COMMA).append(lineSeparator());
         sb.append("numeric_scale AS 'DECIMAL_DIGITS'").append(TRAILING_COMMA).append(lineSeparator());
         sb.append("10 AS 'NUM_PREC_RADIX'").append(TRAILING_COMMA).append(lineSeparator());
-        sb.append("CASE WHEN is_nullable = 'YES' THEN 1 else 0 END AS 'NULLABLE'").append(TRAILING_COMMA)
-        .append(lineSeparator());
+        sb.append("CASE WHEN is_nullable = 'YES' THEN 1 else 0 END AS 'NULLABLE'")
+            .append(TRAILING_COMMA)
+            .append(lineSeparator());
         sb.append("comment as 'REMARKS'").append(TRAILING_COMMA).append(lineSeparator());
         sb.append("column_default AS 'COLUMN_DEF'").append(TRAILING_COMMA).append(lineSeparator());
         sb.append("NULL AS 'SQL_DATA_TYPE'").append(TRAILING_COMMA).append(lineSeparator());
diff --git a/src/test/java/org/duckdb/TestMetadata.java b/src/test/java/org/duckdb/TestMetadata.java
index f4795bd05..a79642ede 100644
--- a/src/test/java/org/duckdb/TestMetadata.java
+++ b/src/test/java/org/duckdb/TestMetadata.java
@@ -11,14 +11,11 @@ import java.util.*;
 
 public class TestMetadata {
 
-    private static void assertNonSystemTables(ResultSet rs, String name) throws Exception
-    {
+    private static void assertNonSystemTables(ResultSet rs, String name) throws Exception {
         assertTrue(rs.next());
-        while(true)
-        {
+        while (true) {
             String type = rs.getString("TABLE_TYPE");
-            if(type.equals("SYSTEM VIEW") || type.equals("SYSTEM TABLE"))
-            {
+            if (type.equals("SYSTEM VIEW") || type.equals("SYSTEM TABLE")) {
                 assertTrue(rs.next());
                 continue;
             }
@@ -47,7 +44,7 @@ public class TestMetadata {
             try (ResultSet rs = dm.getTables(null, null, null, new String[] {})) {
                 assertNonSystemTables(rs, "b");
                 assertNonSystemTables(rs, "a1");
-                assertNonSystemTables(rs,"a2");
+                assertNonSystemTables(rs, "a2");
                 assertNonSystemTables(rs, "c");
                 assertFalse(rs.next());
             }
@@ -557,7 +554,8 @@ public class TestMetadata {
                 assertFalse(rs.next());
             }
 
-            try (ResultSet rs = md.getTables(null, DuckDBConnection.DEFAULT_SCHEMA, "a", new String[] {"TABLE", "VIEW"})) {
+            try (ResultSet rs =
+                     md.getTables(null, DuckDBConnection.DEFAULT_SCHEMA, "a", new String[] {"TABLE", "VIEW"})) {
                 assertTrue(rs.next());
                 assertTrue(rs.getObject("TABLE_CAT") != null);
                 assertEquals(rs.getString("TABLE_SCHEM"), DuckDBConnection.DEFAULT_SCHEMA);
@@ -799,7 +797,7 @@ public class TestMetadata {
     }
 
     public static void test_get_table_types() throws Exception {
-        String[] tableTypesArray = new String[] {"TABLE", "LOCAL TEMPORARY", "VIEW" , "SYSTEM VIEW"};
+        String[] tableTypesArray = new String[] {"TABLE", "LOCAL TEMPORARY", "VIEW", "SYSTEM VIEW"};
         List<String> tableTypesList = new ArrayList<>(asList(tableTypesArray));
         tableTypesList.sort(Comparator.naturalOrder());
 

[staticlibs]

Thanks!