diff --git a/pom.xml b/pom.xml
index 4fda1fb..5cf34b9 100644
--- a/pom.xml
+++ b/pom.xml
@@ -4,7 +4,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.yanghuanglin</groupId>
     <artifactId>seq</artifactId>
-    <version>1.5.1</version>
+    <version>1.5.2</version>
     <name>seq</name>
     <description>seq</description>
     <properties>
diff --git a/src/main/java/com/yanghuanglin/seq/dao/impl/SequencesDaoImpl.java b/src/main/java/com/yanghuanglin/seq/dao/impl/SequencesDaoImpl.java
index 25a1890..5e54f60 100644
--- a/src/main/java/com/yanghuanglin/seq/dao/impl/SequencesDaoImpl.java
+++ b/src/main/java/com/yanghuanglin/seq/dao/impl/SequencesDaoImpl.java
@@ -57,9 +57,9 @@ public class SequencesDaoImpl implements SequencesDao {
     @Override
     public void createTable() {
         String sql = "CREATE TABLE IF NOT EXISTS `%s` ( " +
-                " `%s` VARCHAR ( 255 ) NOT NULL COMMENT '序号英文名称'," +
-                " `%s` VARCHAR ( 255 ) NOT NULL COMMENT '序号类型'," +
-                " `%s` BIGINT ( 2 ) NOT NULL COMMENT '已使用到的序号'," +
+                " `%s` VARCHAR ( 64 ) NOT NULL COMMENT '序号英文名称'," +
+                " `%s` VARCHAR ( 64 ) NOT NULL COMMENT '序号类型'," +
+                " `%s` BIGINT ( 20 ) NOT NULL COMMENT '已使用到的序号'," +
                 " PRIMARY KEY ( `%s`, `%s` ) " +
                 " ) COMMENT '当前序号表'";
         sql = String.format(sql, tableConfig.getTable(),
diff --git a/src/main/java/com/yanghuanglin/seq/dao/impl/SequencesUnlockDaoImpl.java b/src/main/java/com/yanghuanglin/seq/dao/impl/SequencesUnlockDaoImpl.java
index ec50a3a..c5445bf 100644
--- a/src/main/java/com/yanghuanglin/seq/dao/impl/SequencesUnlockDaoImpl.java
+++ b/src/main/java/com/yanghuanglin/seq/dao/impl/SequencesUnlockDaoImpl.java
@@ -72,9 +72,9 @@ public class SequencesUnlockDaoImpl implements SequencesUnlockDao {
     @Override
     public void createTable() {
         String sql = "CREATE TABLE IF NOT EXISTS `%s_unlock` ( " +
-                " `%s` VARCHAR ( 255 ) NOT NULL COMMENT '序号英文名称'," +
-                " `%s` VARCHAR ( 255 ) NOT NULL COMMENT '序号类型'," +
-                " `%s` BIGINT ( 2 ) NOT NULL COMMENT '尚未锁定的序号'," +
+                " `%s` VARCHAR ( 64 ) NOT NULL COMMENT '序号英文名称'," +
+                " `%s` VARCHAR ( 64 ) NOT NULL COMMENT '序号类型'," +
+                " `%s` BIGINT ( 20 ) NOT NULL COMMENT '尚未锁定的序号'," +
                 " `%s` DATETIME NOT NULL COMMENT '使用时间'," +
                 " PRIMARY KEY ( `%s`, `%s` ,`%s` ) " +
                 " ) COMMENT '未锁定序号表'";
diff --git a/src/main/java/com/yanghuanglin/seq/dao/impl/SequencesUnusedDaoImpl.java b/src/main/java/com/yanghuanglin/seq/dao/impl/SequencesUnusedDaoImpl.java
index 4244612..67d5184 100644
--- a/src/main/java/com/yanghuanglin/seq/dao/impl/SequencesUnusedDaoImpl.java
+++ b/src/main/java/com/yanghuanglin/seq/dao/impl/SequencesUnusedDaoImpl.java
@@ -91,9 +91,9 @@ public class SequencesUnusedDaoImpl implements SequencesUnusedDao {
     @Override
     public void createTable() {
         String sql = "CREATE TABLE IF NOT EXISTS `%s_unused` ( " +
-                " `%s` VARCHAR ( 255 ) NOT NULL COMMENT '序号英文名称'," +
-                " `%s` VARCHAR ( 255 ) NOT NULL COMMENT '序号类型'," +
-                " `%s` BIGINT ( 2 ) NOT NULL COMMENT '闲置的的序号'," +
+                " `%s` VARCHAR ( 64 ) NOT NULL COMMENT '序号英文名称'," +
+                " `%s` VARCHAR ( 64 ) NOT NULL COMMENT '序号类型'," +
+                " `%s` BIGINT ( 20 ) NOT NULL COMMENT '闲置的的序号'," +
                 " `%s` DATETIME NOT NULL COMMENT '设为闲置序号的时间'," +
                 " PRIMARY KEY ( `%s`, `%s`, `%s` ) " +
                 " ) COMMENT '闲置序号表'";
diff --git a/src/main/java/com/yanghuanglin/seq/po/Sequences.java b/src/main/java/com/yanghuanglin/seq/po/Sequences.java
index 58d1bdb..74c4466 100644
--- a/src/main/java/com/yanghuanglin/seq/po/Sequences.java
+++ b/src/main/java/com/yanghuanglin/seq/po/Sequences.java
@@ -129,9 +129,9 @@ public class Sequences {
      * @return 补零后的序号，若未单独设置序号的长度，则最小长度为{@link BaseConfig#getMinLength()}长度；否则为修改后的长度，不足部分补零
      */
     public String format() {
-        BaseConfig baseConfig = BaseConfig.getInstance();
-        if (baseConfig.getMinLength() != null)
-            return String.format("%0" + baseConfig.getMinLength() + "d", this.seq);
+        Integer minLength = BaseConfig.getInstance().getMinLength();
+        if (minLength != null)
+            return String.format("%0" + minLength + "d", this.seq);
         return String.valueOf(this.seq);
     }