diff --git a/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/convert/ByteArrayToBytesCharSeqConverter.java b/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/convert/ByteArrayToBytesCharSeqConverter.java
new file mode 100644
index 00000000..a0fc924f
--- /dev/null
+++ b/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/convert/ByteArrayToBytesCharSeqConverter.java
@@ -0,0 +1,28 @@
+/*
+ * Licensed 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.
+ */
+
+package com.github.housepower.jdbc.convert;
+
+import com.github.housepower.misc.BytesCharSeq;
+
+import javax.annotation.concurrent.ThreadSafe;
+
+@ThreadSafe
+public class ByteArrayToBytesCharSeqConverter implements Converter<byte[], BytesCharSeq> {
+
+    @Override
+    public BytesCharSeq convert(byte[] source) {
+        return new BytesCharSeq(source);
+    }
+}
diff --git a/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/convert/BytesCharSeqToByteArrayConverter.java b/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/convert/BytesCharSeqToByteArrayConverter.java
new file mode 100644
index 00000000..e0bb5d9e
--- /dev/null
+++ b/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/convert/BytesCharSeqToByteArrayConverter.java
@@ -0,0 +1,28 @@
+/*
+ * Licensed 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.
+ */
+
+package com.github.housepower.jdbc.convert;
+
+import com.github.housepower.misc.BytesCharSeq;
+
+import javax.annotation.concurrent.ThreadSafe;
+
+@ThreadSafe
+public class BytesCharSeqToByteArrayConverter implements Converter<BytesCharSeq, byte[]> {
+
+    @Override
+    public byte[] convert(BytesCharSeq source) {
+        return source.bytes();
+    }
+}
diff --git a/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/convert/Converter.java b/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/convert/Converter.java
new file mode 100644
index 00000000..7df6a2db
--- /dev/null
+++ b/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/convert/Converter.java
@@ -0,0 +1,48 @@
+/*
+ * Licensed 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.
+ */
+
+package com.github.housepower.jdbc.convert;
+
+import javax.annotation.concurrent.ThreadSafe;
+import java.lang.reflect.ParameterizedType;
+
+/**
+ * A converter converts a source object of type {@code S} to a target of type {@code T}.
+ *
+ * @param <S> the source type
+ * @param <T> the target type
+ */
+@ThreadSafe
+@FunctionalInterface
+public interface Converter<S, T> {
+
+    /**
+     * Convert the source object of type {@code S} to target type {@code T}.
+     *
+     * @param source the source object to convert, which must be an instance of {@code S}
+     * @return the converted object, which must be an instance of {@code T}
+     * @throws IllegalArgumentException if the source cannot be converted to the desired target type
+     */
+    T convert(S source);
+
+    @SuppressWarnings("unchecked")
+    default Class<S> sourceType() {
+        return (Class<S>) ((ParameterizedType) this.getClass().getGenericInterfaces()[0]).getActualTypeArguments()[0];
+    }
+
+    @SuppressWarnings("unchecked")
+    default Class<T> targetType() {
+        return (Class<T>) ((ParameterizedType) this.getClass().getGenericInterfaces()[0]).getActualTypeArguments()[1];
+    }
+}
diff --git a/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/type/JdbcDataType.java b/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/type/JdbcDataType.java
new file mode 100644
index 00000000..994b615f
--- /dev/null
+++ b/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/type/JdbcDataType.java
@@ -0,0 +1,34 @@
+/*
+ * Licensed 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.
+ */
+
+package com.github.housepower.jdbc.type;
+
+public interface JdbcDataType<JDBC> {
+
+    int sqlTypeId();
+
+    Class<JDBC> javaType();
+
+    boolean nullable();
+
+    int getPrecision();
+
+    int getScale();
+
+    boolean isSigned();
+
+    default String format(JDBC value) {
+        return value.toString();
+    }
+}
diff --git a/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/type/JdbcDataTypeFactory.java b/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/type/JdbcDataTypeFactory.java
new file mode 100644
index 00000000..f184c9fd
--- /dev/null
+++ b/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/type/JdbcDataTypeFactory.java
@@ -0,0 +1,19 @@
+/*
+ * Licensed 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.
+ */
+
+package com.github.housepower.jdbc.type;
+
+public class JdbcDataTypeFactory {
+
+}
diff --git a/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/type/JdbcDecimal.java b/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/type/JdbcDecimal.java
new file mode 100644
index 00000000..9513cbe4
--- /dev/null
+++ b/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/type/JdbcDecimal.java
@@ -0,0 +1,37 @@
+/*
+ * Licensed 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.
+ */
+
+package com.github.housepower.jdbc.type;
+
+import com.github.housepower.data.IDataType;
+
+import java.math.BigDecimal;
+import java.sql.Types;
+
+public class JdbcDecimal extends WrappedJdbcDataType<BigDecimal> {
+
+    public JdbcDecimal(IDataType<BigDecimal, BigDecimal> ckDataType) {
+        super(ckDataType);
+    }
+
+    @Override
+    public int sqlTypeId() {
+        return Types.DECIMAL;
+    }
+
+    @Override
+    public Class<BigDecimal> javaType() {
+        return BigDecimal.class;
+    }
+}
diff --git a/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/type/WrappedJdbcDataType.java b/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/type/WrappedJdbcDataType.java
new file mode 100644
index 00000000..3dea0292
--- /dev/null
+++ b/clickhouse-native-jdbc/src/main/java/com/github/housepower/jdbc/type/WrappedJdbcDataType.java
@@ -0,0 +1,51 @@
+/*
+ * Licensed 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.
+ */
+
+package com.github.housepower.jdbc.type;
+
+import com.github.housepower.data.IDataType;
+
+public abstract class WrappedJdbcDataType<JDBC> implements JdbcDataType<JDBC> {
+
+    protected final IDataType<JDBC, JDBC> ckDataType;
+
+    protected WrappedJdbcDataType(IDataType<JDBC, JDBC> ckDataType) {
+        this.ckDataType = ckDataType;
+    }
+
+    @Override
+    public boolean nullable() {
+        return ckDataType.nullable();
+    }
+
+    @Override
+    public int getPrecision() {
+        return ckDataType.getPrecision();
+    }
+
+    @Override
+    public int getScale() {
+        return ckDataType.getScale();
+    }
+
+    @Override
+    public boolean isSigned() {
+        return ckDataType.isSigned();
+    }
+
+    @Override
+    public String format(JDBC value) {
+        return ckDataType.serializeText(value);
+    }
+}