diff --git a/README.md b/README.md
index e6bb77de..51660f14 100644
--- a/README.md
+++ b/README.md
@@ -248,9 +248,10 @@ jdbc驱动名称：com.microsoft.sqlserver.jdbc.SQLServerDriver
 **Sybase数据库**
 
 ```
-jdbc连接地址：jdbc:sybase:Tds:172.17.2.10:5000/test
+jdbc连接地址：jdbc:sybase:Tds:172.17.2.10:5000/test?charset=cp936
 jdbc驱动名称：com.sybase.jdbc4.jdbc.SybDriver
 ```
+> JDBC连接Sybase数据库使用中文时只能使用CP936这个字符集
 
 **PostgreSQL/Greenplum数据库**
 
diff --git a/dbswitch-core/src/main/java/com/gitee/dbswitch/core/database/impl/DatabaseDmImpl.java b/dbswitch-core/src/main/java/com/gitee/dbswitch/core/database/impl/DatabaseDmImpl.java
index ed12bdf6..09503d00 100644
--- a/dbswitch-core/src/main/java/com/gitee/dbswitch/core/database/impl/DatabaseDmImpl.java
+++ b/dbswitch-core/src/main/java/com/gitee/dbswitch/core/database/impl/DatabaseDmImpl.java
@@ -99,6 +99,13 @@ public class DatabaseDmImpl extends AbstractDatabase implements IDatabaseInterfa
     return String.format("explain %s", sql.replace(";", ""));
   }
 
+  /**
+   * https://eco.dameng.com/document/dm/zh-cn/sql-dev/dmpl-sql-datatype.html
+   * <p>
+   * https://eco.dameng.com/document/dm/zh-cn/pm/dm8_sql-data-types-operators.html
+   * <p>
+   * 违反表[xxx]唯一性约束: https://www.cnblogs.com/theli/p/12858875.html
+   */
   @Override
   public String getFieldDefinition(ColumnMetaData v, List<String> pks, boolean useAutoInc,
       boolean addCr, boolean withRemarks) {
@@ -123,33 +130,31 @@ public class DatabaseDmImpl extends AbstractDatabase implements IDatabaseInterfa
         break;
       case ColumnMetaData.TYPE_NUMBER:
       case ColumnMetaData.TYPE_BIGNUMBER:
-        retval.append("NUMBER");
-        if (length > 0) {
-          if (length > 38) {
-            length = 38;
-          }
+        if (null != pks && !pks.isEmpty() && pks.contains(fieldname)) {
+          retval.append("BIGINT");
+        } else {
+          retval.append("NUMERIC");
+          if (length > 0) {
+            if (length > 38) {
+              length = 38;
+            }
 
-          retval.append('(').append(length);
-          if (precision > 0) {
-            retval.append(", ").append(precision);
+            retval.append('(').append(length);
+            if (precision > 0) {
+              retval.append(", ").append(precision);
+            }
+            retval.append(')');
           }
-          retval.append(')');
         }
         break;
       case ColumnMetaData.TYPE_INTEGER:
-        retval.append("INTEGER");
+        retval.append("BIGINT");
         break;
       case ColumnMetaData.TYPE_STRING:
-        if (2 * length >= AbstractDatabase.CLOB_LENGTH) {
-          retval.append("CLOB");
+        if (null != pks && pks.contains(fieldname)) {
+          retval.append("VARCHAR(" + length + ")");
         } else {
-          if (length == 1) {
-            retval.append("NVARCHAR2(2)");
-          } else if (length > 0 && length < 2048) {
-            retval.append("NVARCHAR2(").append(2 * length).append(')');
-          } else {
-            retval.append("CLOB");
-          }
+          retval.append("TEXT");
         }
         break;
       case ColumnMetaData.TYPE_BINARY:
diff --git a/dbswitch-core/src/main/java/com/gitee/dbswitch/core/database/impl/DatabaseSybaseImpl.java b/dbswitch-core/src/main/java/com/gitee/dbswitch/core/database/impl/DatabaseSybaseImpl.java
index 38fcf0fb..8462aa6b 100644
--- a/dbswitch-core/src/main/java/com/gitee/dbswitch/core/database/impl/DatabaseSybaseImpl.java
+++ b/dbswitch-core/src/main/java/com/gitee/dbswitch/core/database/impl/DatabaseSybaseImpl.java
@@ -181,7 +181,7 @@ public class DatabaseSybaseImpl extends AbstractDatabase implements IDatabaseInt
         }
         break;
       case ColumnMetaData.TYPE_BOOLEAN:
-        retval += "BOOLEAN";
+        retval += "TINYINT";
         if (null != pks && !pks.isEmpty() && pks.contains(fieldname)) {
           retval += " NOT NULL";
         }
diff --git a/dbswitch-data/src/main/java/com/gitee/dbswitch/data/handler/MigrationHandler.java b/dbswitch-data/src/main/java/com/gitee/dbswitch/data/handler/MigrationHandler.java
index 5b2ea104..54a538a1 100644
--- a/dbswitch-data/src/main/java/com/gitee/dbswitch/data/handler/MigrationHandler.java
+++ b/dbswitch-data/src/main/java/com/gitee/dbswitch/data/handler/MigrationHandler.java
@@ -78,6 +78,7 @@ public class MigrationHandler implements Supplier<Long> {
   // 目的端
   private final HikariDataSource targetDataSource;
   private ProductTypeEnum targetProductType;
+  private Set<String> targetExistTables;
   private String targetSchemaName;
   private String targetTableName;
   private List<ColumnDescription> targetColumnDescriptions;
@@ -90,15 +91,17 @@ public class MigrationHandler implements Supplier<Long> {
       DbswichProperties properties,
       Integer sourcePropertiesIndex,
       HikariDataSource sds,
-      HikariDataSource tds) {
-    return new MigrationHandler(td, properties, sourcePropertiesIndex, sds, tds);
+      HikariDataSource tds,
+      Set<String> targetExistTables) {
+    return new MigrationHandler(td, properties, sourcePropertiesIndex, sds, tds, targetExistTables);
   }
 
   private MigrationHandler(TableDescription td,
       DbswichProperties properties,
       Integer sourcePropertiesIndex,
       HikariDataSource sds,
-      HikariDataSource tds) {
+      HikariDataSource tds,
+      Set<String> targetExistTables) {
     this.sourceSchemaName = td.getSchemaName();
     this.sourceTableName = td.getTableName();
     this.properties = properties;
@@ -110,6 +113,7 @@ public class MigrationHandler implements Supplier<Long> {
       fetchSize = sourceProperties.getFetchSize();
     }
 
+    this.targetExistTables = targetExistTables;
     // 获取映射转换后新的表名
     this.targetSchemaName = properties.getTarget().getTargetSchema();
     this.targetTableName = PatterNameUtils.getFinalName(td.getTableName(),
@@ -252,14 +256,7 @@ public class MigrationHandler implements Supplier<Long> {
         throw new RuntimeException("task is interrupted");
       }
 
-      IMetaDataByDatasourceService metaDataByDatasourceService =
-          new MetaDataByDataSourceServiceImpl(targetDataSource, targetProductType);
-      List<String> targetTableNames = metaDataByDatasourceService
-          .queryTableList(targetSchemaName)
-          .stream().map(TableDescription::getTableName)
-          .collect(Collectors.toList());
-
-      if (!targetTableNames.contains(targetSchemaName)) {
+      if (!targetExistTables.contains(targetTableName)) {
         // 当目标端不存在该表时，则生成建表语句并创建
         List<String> sqlCreateTable = sourceMetaDataService.getDDLCreateTableSQL(
             targetProductType,
@@ -289,6 +286,8 @@ public class MigrationHandler implements Supplier<Long> {
       // 判断是否具备变化量同步的条件：（1）两端表结构一致，且都有一样的主键字段；(2)MySQL使用Innodb引擎；
       if (properties.getTarget().getChangeDataSync()) {
         // 根据主键情况判断同步的方式：增量同步或覆盖同步
+        IMetaDataByDatasourceService metaDataByDatasourceService =
+            new MetaDataByDataSourceServiceImpl(targetDataSource, targetProductType);
         List<String> dbTargetPks = metaDataByDatasourceService.queryTablePrimaryKeys(
             targetSchemaName, targetTableName);
 
diff --git a/dbswitch-data/src/main/java/com/gitee/dbswitch/data/service/MigrationService.java b/dbswitch-data/src/main/java/com/gitee/dbswitch/data/service/MigrationService.java
index 057de05c..1268ace8 100644
--- a/dbswitch-data/src/main/java/com/gitee/dbswitch/data/service/MigrationService.java
+++ b/dbswitch-data/src/main/java/com/gitee/dbswitch/data/service/MigrationService.java
@@ -24,12 +24,14 @@ import com.zaxxer.hikari.HikariDataSource;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
+import java.util.Set;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.function.Function;
 import java.util.function.Supplier;
 import java.util.regex.Pattern;
+import java.util.stream.Collectors;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.core.task.AsyncTaskExecutor;
 import org.springframework.stereotype.Service;
@@ -103,6 +105,9 @@ public class MigrationService {
     //log.info("Application properties configuration \n{}", properties);
 
     try (HikariDataSource targetDataSource = DataSourceUtils.createTargetDataSource(properties.getTarget())) {
+      IMetaDataByDatasourceService tdsService = new MetaDataByDataSourceServiceImpl(targetDataSource);
+      Set<String> tablesAlreadyExist = tdsService.queryTableList(properties.getTarget().getTargetSchema())
+          .stream().map(TableDescription::getTableName).collect(Collectors.toSet());
       int sourcePropertiesIndex = 0;
       int totalTableCount = 0;
       List<SourceDataSourceProperties> sourcesProperties = properties.getSource();
@@ -160,19 +165,19 @@ public class MigrationService {
                 if (useExcludeTables) {
                   if (!filters.contains(tableName)) {
                     futures.add(
-                        makeFutureTask(td, indexInternal, sourceDataSource, targetDataSource,
+                        makeFutureTask(td, indexInternal, sourceDataSource, targetDataSource, tablesAlreadyExist,
                             numberOfFailures, totalBytesSize));
                   }
                 } else {
                   if (includes.size() == 1 && (includes.get(0).contains("*") || includes.get(0).contains("?"))) {
                     if (Pattern.matches(includes.get(0), tableName)) {
                       futures.add(
-                          makeFutureTask(td, indexInternal, sourceDataSource, targetDataSource,
+                          makeFutureTask(td, indexInternal, sourceDataSource, targetDataSource, tablesAlreadyExist,
                               numberOfFailures, totalBytesSize));
                     }
                   } else if (includes.contains(tableName)) {
                     futures.add(
-                        makeFutureTask(td, indexInternal, sourceDataSource, targetDataSource,
+                        makeFutureTask(td, indexInternal, sourceDataSource, targetDataSource, tablesAlreadyExist,
                             numberOfFailures, totalBytesSize));
                   }
                 }
@@ -222,6 +227,7 @@ public class MigrationService {
    * @param indexInternal    源端索引号
    * @param sds              源端的DataSource数据源
    * @param tds              目的端的DataSource数据源
+   * @param exists           目的端已经存在的表名列表
    * @param numberOfFailures 失败的数量
    * @param totalBytesSize   同步的字节大小
    * @return CompletableFuture<Void>
@@ -231,10 +237,11 @@ public class MigrationService {
       Integer indexInternal,
       HikariDataSource sds,
       HikariDataSource tds,
+      Set<String> exists,
       AtomicInteger numberOfFailures,
       AtomicLong totalBytesSize) {
     return CompletableFuture
-        .supplyAsync(getMigrateHandler(td, indexInternal, sds, tds), this.taskExecutor)
+        .supplyAsync(getMigrateHandler(td, indexInternal, sds, tds, exists), this.taskExecutor)
         .exceptionally(getExceptHandler(td, numberOfFailures))
         .thenAccept(totalBytesSize::addAndGet);
   }
@@ -246,14 +253,16 @@ public class MigrationService {
    * @param indexInternal 源端索引号
    * @param sds           源端的DataSource数据源
    * @param tds           目的端的DataSource数据源
+   * @param exists        目的端已经存在的表名列表
    * @return Supplier<Long>
    */
   private Supplier<Long> getMigrateHandler(
       TableDescription td,
       Integer indexInternal,
       HikariDataSource sds,
-      HikariDataSource tds) {
-    MigrationHandler instance = MigrationHandler.createInstance(td, properties, indexInternal, sds, tds);
+      HikariDataSource tds,
+      Set<String> exists) {
+    MigrationHandler instance = MigrationHandler.createInstance(td, properties, indexInternal, sds, tds, exists);
     migrationHandlers.add(instance);
     return instance;
   }