More data type aliases, return scale for number and datetime, and bet…

…ter binary string support

clickhouse-client/src/main/java/com/clickhouse/client/ClickHouseDataType.java

@@ -74,10 +74,11 @@ public enum ClickHouseDataType {
     IPv6(Inet6Address.class, false, true, false, 16, 39, 0, 0, 0, "INET6"),
     FixedString(String.class, true, true, false, 0, 0, 0, 0, 0, "BINARY"),
     String(String.class, false, true, false, 0, 0, 0, 0, 0, "BINARY LARGE OBJECT", "BINARY VARYING", "BLOB", "BYTEA",
-            "CHAR", "CHAR LARGE OBJECT", "CHAR VARYING", "CHARACTER", "CHARACTER LARGE OBJECT", "CHARACTER VARYING",
-            "CLOB", "LONGBLOB", "LONGTEXT", "MEDIUMBLOB", "MEDIUMTEXT", "NATIONAL CHAR", "NATIONAL CHAR VARYING",
-            "NATIONAL CHARACTER", "NATIONAL CHARACTER LARGE OBJECT", "NATIONAL CHARACTER VARYING", "NCHAR",
-            "NCHAR LARGE OBJECT", "NCHAR VARYING", "NVARCHAR", "TEXT", "TINYBLOB", "TINYTEXT", "VARCHAR", "VARCHAR2"),
+            "CHAR", "CHARACTER", "CHARACTER LARGE OBJECT", "CHARACTER VARYING", "CHAR LARGE OBJECT", "CHAR VARYING",
+            "CLOB", "LONGBLOB", "LONGTEXT", "MEDIUMBLOB", "MEDIUMTEXT", "NATIONAL CHAR", "NATIONAL CHARACTER",
+            "NATIONAL CHARACTER LARGE OBJECT", "NATIONAL CHARACTER VARYING", "NATIONAL CHAR VARYING", "NCHAR",
+            "NCHAR LARGE OBJECT", "NCHAR VARYING", "NVARCHAR", "TEXT", "TINYBLOB", "TINYTEXT", "VARBINARY", "VARCHAR",
+            "VARCHAR2"),
     AggregateFunction(String.class, true, true, false, 0, 0, 0, 0, 0), // implementation-defined intermediate state
     SimpleAggregateFunction(String.class, true, true, false, 0, 0, 0, 0, 0),
     Array(Object.class, true, true, false, 0, 0, 0, 0, 0),

clickhouse-client/src/main/java/com/clickhouse/client/ClickHouseValue.java

@@ -538,6 +538,55 @@ default <T, E extends Enum<E>> T asObject(Class<T> clazz) {
         }
     }
 
+    /**
+     * Gets binary value as byte array.
+     *
+     * @return non-null byte array
+     */
+    default byte[] asBinary() {
+        return asBinary(0, null);
+    }
+
+    /**
+     * Gets binary value as fixed length byte array.
+     *
+     * @param length byte length of value, 0 or negative number means no limit
+     * @return non-null byte array
+     */
+    default byte[] asBinary(int length) {
+        return asBinary(length, null);
+    }
+
+    /**
+     * Gets binary value as byte array.
+     *
+     * @param charset charset, null is same as default(UTF-8)
+     * @return non-null byte array
+     */
+    default byte[] asBinary(Charset charset) {
+        return asBinary(0, charset);
+    }
+
+    /**
+     * Gets binary value as byte array.
+     *
+     * @param length  byte length of value, 0 or negative number means no limit
+     * @param charset charset, null is same as default(UTF-8)
+     * @return non-null byte array
+     */
+    default byte[] asBinary(int length, Charset charset) {
+        if (isNullOrEmpty()) {
+            return ClickHouseValues.EMPTY_BYTE_ARRAY;
+        }
+
+        byte[] bytes = asString().getBytes(charset == null ? StandardCharsets.UTF_8 : charset);
+        if (length > 0) {
+            ClickHouseChecker.notWithDifferentLength(bytes, length);
+        }
+
+        return bytes;
+    }
+
     /**
      * Gets value as unbounded string, using default charset(usually UTF-8).
      *

clickhouse-client/src/main/java/com/clickhouse/client/ClickHouseValues.java

@@ -76,7 +76,9 @@ public final class ClickHouseValues {
     public static final long[] EMPTY_LONG_ARRAY = new long[0];
     public static final float[] EMPTY_FLOAT_ARRAY = new float[0];
     public static final double[] EMPTY_DOUBLE_ARRAY = new double[0];
+
     public static final String EMPTY_ARRAY_EXPR = "[]";
+    public static final String EMPTY_STRING_EXPR = "''";
 
     public static final BigDecimal NANOS = new BigDecimal(BigInteger.TEN.pow(9));
 

clickhouse-client/src/main/java/com/clickhouse/client/data/ClickHouseRowBinaryProcessor.java

@@ -331,13 +331,15 @@ private void buildMappingsForDataTypes() {
 
             // string and uuid
             buildMappings(deserializers, serializers,
-                    (r, f, c, i) -> ClickHouseStringValue.of(r, BinaryStreamUtils.readFixedString(i, c.getPrecision())),
-                    (v, f, c, o) -> BinaryStreamUtils.writeFixedString(o, v.asString(c.getPrecision()),
-                            c.getPrecision()),
-                    ClickHouseDataType.FixedString);
-            buildMappings(deserializers, serializers,
-                    (r, f, c, i) -> ClickHouseStringValue.of(r, i.readUnicodeString()),
-                    (v, f, c, o) -> BinaryStreamUtils.writeString(o, v.asString()), ClickHouseDataType.String);
+                    (r, f, c, i) -> ClickHouseStringValue.of(r, i.readBytes(c.getPrecision())),
+                    (v, f, c, o) -> o.write(v.asBinary(c.getPrecision())), ClickHouseDataType.FixedString);
+            buildMappings(deserializers, serializers,
+                    (r, f, c, i) -> ClickHouseStringValue.of(r, i.readBytes(i.readVarInt())),
+                    (v, f, c, o) -> {
+                        byte[] bytes = v.asBinary();
+                        BinaryStreamUtils.writeVarInt(o, bytes.length);
+                        o.write(bytes);
+                    }, ClickHouseDataType.String);
             buildMappings(deserializers, serializers,
                     (r, f, c, i) -> ClickHouseUuidValue.of(r, BinaryStreamUtils.readUuid(i)),
                     (v, f, c, o) -> BinaryStreamUtils.writeUuid(o, v.asUuid()), ClickHouseDataType.UUID);