[fix][sdk] Support decimal rounding to be compatible with mysql.

Author: nokiaMS

java/dingo-sdk/src/main/java/io/dingodb/sdk/common/serial/MyDecimal.java

@@ -434,6 +434,15 @@ public MyDecimal(String string, int prec, int scal) {
             throw new IllegalArgumentException("Decimal type: No digits in string.");
         }
 
+        //To be compatible with MySQL rounding for decimal.
+        if(digitsFracLocal != 0 && scal < digitsFracLocal) {
+            int lastDigitPos = 1 - ((negative) ? 1 : 0);
+            int lastDigit = Integer.parseInt(String.valueOf(string.charAt(digitsIntLocal + digitsFracLocal - lastDigitPos)));
+            lastDigit = lastDigit < 5 ? lastDigit : lastDigit + 1;
+            string = string.substring(0, digitsIntLocal + digitsFracLocal - lastDigitPos) + lastDigit;
+            digitsFracLocal = scal;
+        }
+
         int wordsInt = digitsToWords(digitsIntLocal);
         int wordsFrac = digitsToWords(digitsFracLocal);
 

java/dingo-sdk/src/test/java/sdk/common/serial/CodecTest.java

@@ -67,6 +67,96 @@ public void testDecimal1() throws IOException {
         Assertions.assertArrayEquals(expected, codec.decode(codec.encode(record)));
     }
 
+    @Test
+    public void testDecimal1_1() throws IOException {
+
+        ColumnDefinition c1 = ColumnDefinition.builder().name("col1").type("DECIMAL").primary(0).precision(10).scale(2).build();
+        ColumnDefinition c2 = ColumnDefinition.builder().name("col2").type("INT").primary(-1).build();
+
+        TableDefinition tableDefinition = TableDefinition.builder()
+                .name("TEST_ENCODE")
+                .columns(Arrays.asList(c1, c2))
+                .version(1).codecVersion(2)
+                .build();
+
+        DingoKeyValueCodec codec = DingoKeyValueCodec.of(1, 1L, tableDefinition);
+        Object[] record = {"1.231234e2", 1};
+        Object[] expected = {"123.12", 1};
+        Assertions.assertArrayEquals(expected, codec.decode(codec.encode(record)));
+    }
+
+    @Test
+    public void testDecimal1_2() throws IOException {
+
+        ColumnDefinition c1 = ColumnDefinition.builder().name("col1").type("DECIMAL").primary(0).precision(10).scale(2).build();
+        ColumnDefinition c2 = ColumnDefinition.builder().name("col2").type("INT").primary(-1).build();
+
+        TableDefinition tableDefinition = TableDefinition.builder()
+                .name("TEST_ENCODE")
+                .columns(Arrays.asList(c1, c2))
+                .version(1).codecVersion(2)
+                .build();
+
+        DingoKeyValueCodec codec = DingoKeyValueCodec.of(1, 1L, tableDefinition);
+        Object[] record = {"2345.678", 1};
+        Object[] expected = {"2345.68", 1};
+        Assertions.assertArrayEquals(expected, codec.decode(codec.encode(record)));
+    }
+
+    @Test
+    public void testDecimal1_3() throws IOException {
+
+        ColumnDefinition c1 = ColumnDefinition.builder().name("col1").type("DECIMAL").primary(0).precision(10).scale(2).build();
+        ColumnDefinition c2 = ColumnDefinition.builder().name("col2").type("INT").primary(-1).build();
+
+        TableDefinition tableDefinition = TableDefinition.builder()
+                .name("TEST_ENCODE")
+                .columns(Arrays.asList(c1, c2))
+                .version(1).codecVersion(2)
+                .build();
+
+        DingoKeyValueCodec codec = DingoKeyValueCodec.of(1, 1L, tableDefinition);
+        Object[] record = {"2345.6", 1};
+        Object[] expected = {"2345.60", 1};
+        Assertions.assertArrayEquals(expected, codec.decode(codec.encode(record)));
+    }
+
+    @Test
+    public void testDecimal1_4() throws IOException {
+
+        ColumnDefinition c1 = ColumnDefinition.builder().name("col1").type("DECIMAL").primary(0).precision(10).scale(2).build();
+        ColumnDefinition c2 = ColumnDefinition.builder().name("col2").type("INT").primary(-1).build();
+
+        TableDefinition tableDefinition = TableDefinition.builder()
+                .name("TEST_ENCODE")
+                .columns(Arrays.asList(c1, c2))
+                .version(1).codecVersion(2)
+                .build();
+
+        DingoKeyValueCodec codec = DingoKeyValueCodec.of(1, 1L, tableDefinition);
+        Object[] record = {"2345", 1};
+        Object[] expected = {"2345.00", 1};
+        Assertions.assertArrayEquals(expected, codec.decode(codec.encode(record)));
+    }
+
+    @Test
+    public void testDecimal1_5() throws IOException {
+
+        ColumnDefinition c1 = ColumnDefinition.builder().name("col1").type("DECIMAL").primary(0).precision(10).scale(2).build();
+        ColumnDefinition c2 = ColumnDefinition.builder().name("col2").type("INT").primary(-1).build();
+
+        TableDefinition tableDefinition = TableDefinition.builder()
+                .name("TEST_ENCODE")
+                .columns(Arrays.asList(c1, c2))
+                .version(1).codecVersion(2)
+                .build();
+
+        DingoKeyValueCodec codec = DingoKeyValueCodec.of(1, 1L, tableDefinition);
+        Object[] record = {"-2345.678", 1};
+        Object[] expected = {"-2345.68", 1};
+        Assertions.assertArrayEquals(expected, codec.decode(codec.encode(record)));
+    }
+
     @Test
     public void testDecimal2() throws IOException {