add StructType behavior

csharp/src/Client/AdbcCommand.cs

@@ -80,6 +80,7 @@ internal AdbcCommand(AdbcStatement adbcStatement, AdbcConnection adbcConnection)
             this._adbcStatement = adbcStatement;
             this.DbConnection = adbcConnection;
             this.DecimalBehavior = adbcConnection.DecimalBehavior;
+            this.StructBehavior = adbcConnection.StructBehavior;
         }
 
         /// <summary>
@@ -90,6 +91,8 @@ internal AdbcCommand(AdbcStatement adbcStatement, AdbcConnection adbcConnection)
 
         public DecimalBehavior DecimalBehavior { get; set; }
 
+        public StructBehavior StructBehavior { get; set; }
+
         public override string CommandText
         {
             get => AdbcStatement.SqlQuery ?? string.Empty;
@@ -204,7 +207,7 @@ protected override DbDataReader ExecuteDbDataReader(CommandBehavior behavior)
                 case CommandBehavior.SchemaOnly:   // The schema is not known until a read happens
                 case CommandBehavior.Default:
                     QueryResult result = this.ExecuteQuery();
-                    return new AdbcDataReader(this, result, this.DecimalBehavior, closeConnection);
+                    return new AdbcDataReader(this, result, this.DecimalBehavior, this.StructBehavior, closeConnection);
 
                 default:
                     throw new InvalidOperationException($"{behavior} is not supported with this provider");

csharp/src/Client/AdbcConnection.cs

@@ -132,6 +132,11 @@ internal AdbcStatement CreateStatement()
         /// </summary>
         public DecimalBehavior DecimalBehavior { get; set; }
 
+        /// <summary>
+        /// Indicates how structs should be treated.
+        /// </summary>
+        public StructBehavior StructBehavior { get; set; } = StructBehavior.JsonString;
+
         protected override DbCommand CreateDbCommand()
         {
             EnsureConnectionOpen();

csharp/src/Client/AdbcDataReader.cs

@@ -61,7 +61,7 @@ public sealed class AdbcDataReader : DbDataReader, IDbColumnSchemaGenerator
         /// </remarks>
         public event GetValueEventHandler? OnGetValue;
 
-        internal AdbcDataReader(AdbcCommand adbcCommand, QueryResult adbcQueryResult, DecimalBehavior decimalBehavior, bool closeConnection)
+        internal AdbcDataReader(AdbcCommand adbcCommand, QueryResult adbcQueryResult, DecimalBehavior decimalBehavior, StructBehavior structBehavior, bool closeConnection)
         {
             if (adbcCommand == null)
                 throw new ArgumentNullException(nameof(adbcCommand));
@@ -82,6 +82,7 @@ internal AdbcDataReader(AdbcCommand adbcCommand, QueryResult adbcQueryResult, De
             this.closeConnection = closeConnection;
             this.isClosed = false;
             this.DecimalBehavior = decimalBehavior;
+            this.StructBehavior = structBehavior;
         }
 
         public override object this[int ordinal] => GetValue(ordinal);
@@ -103,6 +104,8 @@ internal AdbcDataReader(AdbcCommand adbcCommand, QueryResult adbcQueryResult, De
 
         public DecimalBehavior DecimalBehavior { get; set; }
 
+        public StructBehavior StructBehavior { get; set; }
+
         public override int RecordsAffected => this.recordsAffected;
 
         /// <summary>
@@ -318,7 +321,7 @@ public override bool Read()
 
         public override DataTable? GetSchemaTable()
         {
-            return SchemaConverter.ConvertArrowSchema(this.schema, this.adbcCommand.AdbcStatement, this.DecimalBehavior);
+            return SchemaConverter.ConvertArrowSchema(this.schema, this.adbcCommand.AdbcStatement, this.DecimalBehavior, this.StructBehavior);
         }
 
 #if NET5_0_OR_GREATER
@@ -338,7 +341,7 @@ public ReadOnlyCollection<AdbcColumn> GetAdbcColumnSchema()
 
             foreach (Field f in this.schema.FieldsList)
             {
-                Type t = SchemaConverter.ConvertArrowType(f, this.DecimalBehavior);
+                Type t = SchemaConverter.ConvertArrowType(f, this.DecimalBehavior, this.StructBehavior);
 
                 if (f.HasMetadata &&
                     f.Metadata.ContainsKey("precision") &&

csharp/src/Client/SchemaConverter.cs

@@ -33,7 +33,7 @@ internal class SchemaConverter
         /// <param name="schema">The Arrow schema</param>
         /// <param name="adbcStatement">The AdbcStatement to use</param>
         /// <exception cref="ArgumentNullException"></exception>
-        public static DataTable ConvertArrowSchema(Schema schema, AdbcStatement adbcStatement, DecimalBehavior decimalBehavior)
+        public static DataTable ConvertArrowSchema(Schema schema, AdbcStatement adbcStatement, DecimalBehavior decimalBehavior, StructBehavior structBehavior)
         {
             if (schema == null)
                 throw new ArgumentNullException(nameof(schema));
@@ -61,7 +61,7 @@ public static DataTable ConvertArrowSchema(Schema schema, AdbcStatement adbcStat
                 row[SchemaTableColumn.ColumnOrdinal] = columnOrdinal;
                 row[SchemaTableColumn.AllowDBNull] = f.IsNullable;
                 row[SchemaTableColumn.ProviderType] = f.DataType;
-                Type t = ConvertArrowType(f, decimalBehavior);
+                Type t = ConvertArrowType(f, decimalBehavior, structBehavior);
 
                 row[SchemaTableColumn.DataType] = t;
 
@@ -111,7 +111,7 @@ public static DataTable ConvertArrowSchema(Schema schema, AdbcStatement adbcStat
         /// </summary>
         /// <param name="f"></param>
         /// <returns></returns>
-        public static Type ConvertArrowType(Field f, DecimalBehavior decimalBehavior)
+        public static Type ConvertArrowType(Field f, DecimalBehavior decimalBehavior, StructBehavior structBehavior)
         {
             switch (f.DataType.TypeId)
             {
@@ -120,11 +120,11 @@ public static Type ConvertArrowType(Field f, DecimalBehavior decimalBehavior)
                     IArrowType valueType = list.ValueDataType;
                     return GetArrowArrayType(valueType);
                 default:
-                    return GetArrowType(f, decimalBehavior);
+                    return GetArrowType(f, decimalBehavior, structBehavior);
             }
         }
 
-        public static Type GetArrowType(Field f, DecimalBehavior decimalBehavior)
+        public static Type GetArrowType(Field f, DecimalBehavior decimalBehavior, StructBehavior structBehavior)
         {
             switch (f.DataType.TypeId)
             {
@@ -183,7 +183,10 @@ public static Type GetArrowType(Field f, DecimalBehavior decimalBehavior)
                     return typeof(string);
 
                 case ArrowTypeId.Struct:
-                    goto default;
+                    if (structBehavior == StructBehavior.JsonString)
+                        return typeof(string);
+                    else
+                        goto default;
 
                 case ArrowTypeId.Timestamp:
                     return typeof(DateTimeOffset);

csharp/src/Client/StructBehavior.cs

@@ -0,0 +1,32 @@
+/*
+* Licensed to the Apache Software Foundation (ASF) under one or more
+* contributor license agreements.  See the NOTICE file distributed with
+* this work for additional information regarding copyright ownership.
+* The ASF licenses this file to You under the Apache License, Version 2.0
+* (the "License"); you may not use this file except in compliance with
+* the License.  You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+namespace Apache.Arrow.Adbc.Client
+{
+    public enum StructBehavior
+    {
+        /// <summary>
+        /// Serialized as a JSON string
+        /// </summary>
+        JsonString,
+
+        /// <summary>
+        /// Leave as native StructArray
+        /// </summary>
+        Strict
+    }
+}

csharp/test/Apache.Arrow.Adbc.Tests/Client/ClientTests.cs

@@ -114,7 +114,7 @@ private AdbcDataReader GetMoqDataReader(DecimalBehavior decimalBehavior, string
 
             List<RecordBatch> records = new List<RecordBatch>()
             {
-                new RecordBatch(schema, values, values.Count)
+                new RecordBatch(schema, values, array.Length)
             };
 
             MockArrayStream mockArrayStream = new MockArrayStream(schema, records);
@@ -150,7 +150,7 @@ private AdbcDataReader GetMoqDataReaderForIntegers()
 
             List<RecordBatch> records = new List<RecordBatch>()
             {
-                new RecordBatch(schema, values, numbersArray.Count())
+                new RecordBatch(schema, values, numbersArray.Length)
             };
 
             MockArrayStream mockArrayStream = new MockArrayStream(schema, records);

csharp/test/Drivers/Interop/FlightSql/DriverTests.cs

@@ -302,7 +302,7 @@ public void CanGetObjectsAll()
         {
             foreach (FlightSqlTestEnvironment environment in _environments)
             {
-                string databaseName = environment.Metadata.Catalog;
+                string? databaseName = environment.Metadata.Catalog;
                 string? schemaName = environment.Metadata.Schema;
                 string tableName = environment.Metadata.Table;
                 string? columnName = null;

csharp/test/Drivers/Interop/FlightSql/FlightSqlData.cs

@@ -41,18 +41,20 @@ FlightSqlTestEnvironmentType environmentType
         {
             switch (environmentType)
             {
+                case FlightSqlTestEnvironmentType.Denodo:
+                    return GetDenodoSampleData();
+                case FlightSqlTestEnvironmentType.Dremio:
+                    return GetDremioSampleData();
                 case FlightSqlTestEnvironmentType.DuckDB:
                     return GetDuckDbSampleData();
                 case FlightSqlTestEnvironmentType.SQLite:
                     return GetSQLiteSampleData();
-                case FlightSqlTestEnvironmentType.Dremio:
-                    return GetDremioSampleData();
                 default:
                     throw new InvalidOperationException("Unknown environment type.");
             }
         }
 
-        private static SampleDataBuilder GetDuckDbSampleData()
+        private static SampleDataBuilder GetDenodoSampleData()
         {
             SampleDataBuilder sampleDataBuilder = new SampleDataBuilder();
 
@@ -109,43 +111,6 @@ private static SampleDataBuilder GetDuckDbSampleData()
             return sampleDataBuilder;
         }
 
-        private static SampleDataBuilder GetSQLiteSampleData()
-        {
-            string tempTable = Guid.NewGuid().ToString().Replace("-", "");
-
-            SampleDataBuilder sampleDataBuilder = new SampleDataBuilder();
-
-            sampleDataBuilder.Samples.Add(
-                new SampleData()
-                {
-                    // for SQLite, we can't just select data without a
-                    // table because we get mixed schemas that are returned,
-                    // resulting in an error. so create a temp table,
-                    // insert data, select data, then remove the table.
-                    PreQueryCommands = new List<string>()
-                    {
-                            $"CREATE TEMP TABLE [{tempTable}] (INTEGER_COLUMN INTEGER, TEXT_COLUMN TEXT, BLOB_COLUMN BLOB, REAL_COLUMN REAL, NULL_COLUMN NULL);",
-                            $"INSERT INTO [{tempTable}] (INTEGER_COLUMN, TEXT_COLUMN, BLOB_COLUMN, REAL_COLUMN, NULL_COLUMN) VALUES (42, 'Hello, SQLite', X'426C6F62', 3.14159, NULL);"
-                    },
-                    Query = $"SELECT INTEGER_COLUMN, TEXT_COLUMN, BLOB_COLUMN, REAL_COLUMN, NULL_COLUMN FROM [{tempTable}];",
-                    PostQueryCommands = new List<string>()
-                    {
-                            $"DROP TABLE [{tempTable}];"
-                    },
-                    ExpectedValues = new List<ColumnNetTypeArrowTypeValue>()
-                    {
-                          new ColumnNetTypeArrowTypeValue("INTEGER_COLUMN", typeof(long), typeof(Int64Type), 42L),
-                          new ColumnNetTypeArrowTypeValue("TEXT_COLUMN", typeof(string), typeof(StringType), "Hello, SQLite"),
-                          new ColumnNetTypeArrowTypeValue("BLOB_COLUMN", typeof(byte[]), typeof(BinaryType),  Encoding.UTF8.GetBytes("Blob")),
-                          new ColumnNetTypeArrowTypeValue("REAL_COLUMN", typeof(double), typeof(DoubleType), 3.14159d),
-                          new ColumnNetTypeArrowTypeValue("NULL_COLUMN", typeof(UnionType), typeof(UnionType), null),
-                    }
-                }
-            );
-
-            return sampleDataBuilder;
-        }
-
         private static SampleDataBuilder GetDremioSampleData()
         {
             ListArray.Builder labuilder = new ListArray.Builder(Int32Type.Default);
@@ -190,11 +155,105 @@ private static SampleDataBuilder GetDremioSampleData()
 #endif
                             new ColumnNetTypeArrowTypeValue("sample_timestamp", typeof(DateTimeOffset), typeof(TimestampType), new DateTimeOffset(new DateTime(2024, 1, 1, 12, 34, 56), TimeSpan.Zero)),
                             new ColumnNetTypeArrowTypeValue("sample_array", typeof(Int32Array), typeof(ListType), numbersArray),
-                            new ColumnNetTypeArrowTypeValue("sample_struct", typeof(string), typeof(StringType), "{\"name\":\"Gnarly\", \"age\":7, \"car\":null}"),
+                            new ColumnNetTypeArrowTypeValue("sample_struct", typeof(string), typeof(StructType), "{\"name\":\"Gnarly\",\"age\":7}"),
                     }
                 });
 
             return sampleDataBuilder;
         }
+
+        private static SampleDataBuilder GetDuckDbSampleData()
+        {
+            SampleDataBuilder sampleDataBuilder = new SampleDataBuilder();
+
+            sampleDataBuilder.Samples.Add(
+                new SampleData()
+                {
+                    Query = "SELECT " +
+                            "42 AS \"TinyInt\", " +
+                            "12345 AS \"SmallInt\", " +
+                            "987654321 AS \"Integer\", " +
+                            "1234567890123 AS \"BigInt\", " +
+                            "3.141592 AS \"Real\", " +
+                            "123.456789123456 AS \"Double\", " +
+                            "DECIMAL '12345.67' AS \"Decimal\",  " +
+                            "'DuckDB' AS \"Varchar\", " +
+                            "BLOB 'abc' AS \"Blob\", " +
+                            "TRUE AS \"Boolean\"," +
+                            "DATE '2024-09-10' AS \"Date\", " +
+                            "TIME '12:34:56' AS \"Time\", " +
+                            "TIMESTAMP '2024-09-10 12:34:56' AS \"Timestamp\", " +
+                            "INTERVAL '1 year' AS \"Interval\", " +
+                            "'[1, 2, 3]'::JSON AS \"JSON\", " +
+                            "'[{\"key\": \"value\"}]'::JSON AS \"JSON_Array\", " +
+                            "to_json([true, false, null]) AS \"List_JSON\", " + // need to convert List values to json
+                            "to_json(MAP {'key': 'value'}) AS \"Map_JSON\" ", // need to convert Map values to json
+                    ExpectedValues = new List<ColumnNetTypeArrowTypeValue>()
+                    {
+                          new ColumnNetTypeArrowTypeValue("TinyInt", typeof(int), typeof(Int32Type), 42),
+                          new ColumnNetTypeArrowTypeValue("SmallInt", typeof(int), typeof(Int32Type), 12345),
+                          new ColumnNetTypeArrowTypeValue("Integer", typeof(int), typeof(Int32Type), 987654321),
+                          new ColumnNetTypeArrowTypeValue("BigInt", typeof(Int64), typeof(Int64Type), 1234567890123),
+                          new ColumnNetTypeArrowTypeValue("Real", typeof(SqlDecimal), typeof(Decimal128Type), new SqlDecimal(3.141592m)),
+                          new ColumnNetTypeArrowTypeValue("Double", typeof(SqlDecimal), typeof(Decimal128Type), new SqlDecimal(123.456789123456m)),
+                          new ColumnNetTypeArrowTypeValue("Decimal", typeof(SqlDecimal), typeof(Decimal128Type), new SqlDecimal(12345.67m)),
+                          new ColumnNetTypeArrowTypeValue("Varchar", typeof(string), typeof(StringType), "DuckDB"),
+                          new ColumnNetTypeArrowTypeValue("Blob", typeof(byte[]), typeof(BinaryType),  Encoding.UTF8.GetBytes("abc")),
+                          new ColumnNetTypeArrowTypeValue("Boolean", typeof(bool), typeof(BooleanType), true),
+                          new ColumnNetTypeArrowTypeValue("Date", typeof(DateTime), typeof(Date32Type), new DateTime(2024, 09, 10)),
+#if NET6_0_OR_GREATER
+                          new ColumnNetTypeArrowTypeValue("Time", typeof(TimeOnly), typeof(Time64Type), new TimeOnly(12, 34, 56)),
+#else
+                          new ColumnNetTypeArrowTypeValue("Time", typeof(TimeSpan), typeof(Time64Type), new TimeSpan(12, 34, 56)),
+#endif
+                          new ColumnNetTypeArrowTypeValue("Timestamp", typeof(DateTimeOffset), typeof(TimestampType), new DateTimeOffset(new DateTime(2024, 9, 10, 12, 34, 56), TimeSpan.Zero)),
+                          new ColumnNetTypeArrowTypeValue("Interval", typeof(MonthDayNanosecondInterval), typeof(IntervalType), new MonthDayNanosecondInterval(12, 0, 0)),
+                          new ColumnNetTypeArrowTypeValue("JSON", typeof(string), typeof(StringType), "[1, 2, 3]"),
+                          new ColumnNetTypeArrowTypeValue("JSON_Array", typeof(string), typeof(StringType), "[{\"key\": \"value\"}]"),
+                          new ColumnNetTypeArrowTypeValue("List_JSON", typeof(string), typeof(StringType),"[true,false,null]"),
+                          new ColumnNetTypeArrowTypeValue("Map_JSON", typeof(string), typeof(StringType), "{\"key\":\"value\"}"),
+                    }
+                }
+            );
+
+            return sampleDataBuilder;
+        }
+
+        private static SampleDataBuilder GetSQLiteSampleData()
+        {
+            string tempTable = Guid.NewGuid().ToString().Replace("-", "");
+
+            SampleDataBuilder sampleDataBuilder = new SampleDataBuilder();
+
+            sampleDataBuilder.Samples.Add(
+                new SampleData()
+                {
+                    // for SQLite, we can't just select data without a
+                    // table because we get mixed schemas that are returned,
+                    // resulting in an error. so create a temp table,
+                    // insert data, select data, then remove the table.
+                    PreQueryCommands = new List<string>()
+                    {
+                            $"CREATE TEMP TABLE [{tempTable}] (INTEGER_COLUMN INTEGER, TEXT_COLUMN TEXT, BLOB_COLUMN BLOB, REAL_COLUMN REAL, NULL_COLUMN NULL);",
+                            $"INSERT INTO [{tempTable}] (INTEGER_COLUMN, TEXT_COLUMN, BLOB_COLUMN, REAL_COLUMN, NULL_COLUMN) VALUES (42, 'Hello, SQLite', X'426C6F62', 3.14159, NULL);"
+                    },
+                    Query = $"SELECT INTEGER_COLUMN, TEXT_COLUMN, BLOB_COLUMN, REAL_COLUMN, NULL_COLUMN FROM [{tempTable}];",
+                    PostQueryCommands = new List<string>()
+                    {
+                            $"DROP TABLE [{tempTable}];"
+                    },
+                    ExpectedValues = new List<ColumnNetTypeArrowTypeValue>()
+                    {
+                          new ColumnNetTypeArrowTypeValue("INTEGER_COLUMN", typeof(long), typeof(Int64Type), 42L),
+                          new ColumnNetTypeArrowTypeValue("TEXT_COLUMN", typeof(string), typeof(StringType), "Hello, SQLite"),
+                          new ColumnNetTypeArrowTypeValue("BLOB_COLUMN", typeof(byte[]), typeof(BinaryType),  Encoding.UTF8.GetBytes("Blob")),
+                          new ColumnNetTypeArrowTypeValue("REAL_COLUMN", typeof(double), typeof(DoubleType), 3.14159d),
+                          new ColumnNetTypeArrowTypeValue("NULL_COLUMN", typeof(UnionType), typeof(UnionType), null),
+                    }
+                }
+            );
+
+            return sampleDataBuilder;
+        }
     }
 }

csharp/test/Drivers/Interop/FlightSql/FlightSqlTestConfiguration.cs

@@ -49,9 +49,10 @@ internal class FlightSqlTestConfiguration
 
     internal enum FlightSqlTestEnvironmentType
     {
+        Denodo,
+        Dremio,
         DuckDB,
-        SQLite,
-        Dremio
+        SQLite
     }
 
     internal class FlightSqlTestEnvironment : TestConfiguration