各种类型SQL语句解析的代码实现

DDL解析


如果一个Record 是DDL语句，那么这个Record 的操作类型为DDL。且DDL语句存储在第一列的value中。具体获取DDL语句的代码如下： String ddl_string;                  
Record.Type type=record.getOpt();
if(type.equals(Record.Type.DDL)){
    List<DataMessage.Record.Field> fields = record.getFieldList();  
    ddl_string = fields.get(0).getValue().toString();
}


Insert 解析


如果一个Record 是Insert语句，那么这个Record的操作类型为INSERT。具体获取Insert完整语句的代码如下： StringBuilder insert_string=new StringBuilder();
Record.Type type=record.getOpt();
DataMessage.Record.Field field;
StringBuilder FieldName=new StringBuilder();
StringBuilder FieldValue = new StringBuilder();
if(type.equals(Record.Type.INSERT)){
       int i=0;
       List<DataMessage.Record.Field> fields = record.getFieldList();  
       for (; i < fields.size(); i++) {
              field = fields.get(i);                                   FieldName.append('`'+field.getFieldname().toLowerCase()+'`');
              FieldValue.append(field.getValue());
              if (i != fields.size() - 1) {
                      FieldName.append(',');
                      FieldValue.append(',');
              }
        }
        insert_string.append("insert "+ record.getTablename()+"("+FieldName.toString()+") values("+FieldValue.toString()+");");
}


Update 解析


如果一个Record 是Update语句，那么这个Record的操作类型为UPDATE。
update更新前的字段存储在：Record.getFieldList()中索引为偶数的Field，更新后的字段值存储在：索引为奇数的Field。
下面的示例代码介绍当update的表有主键时，获取Insert完整语句的代码示例： StringBuilder update_string=new StringBuilder();                  
Record.Type type=record.getOpt();
DataMessage.Record.Field field;
StringBuilder SetValue = new StringBuilder();
StringBuilder WhereCondition = new StringBuilder();
String ConditionStr;
boolean hasPk=false;
boolean pkMode=false;
boolean hasSet=false;
if(type.equals(Record.Type.UPDATE)){                        
    int i=0;
    DataMessage.Record.Field OldField = null;
    DataMessage.Record.Field NewField = null;
    List<DataMessage.Record.Field> fields = record.getFieldList();
    for (; i <fields.size() ; i++) {
        if (i % 2 == 0) {
            OldField = fields.get(i);
            continue;
        }
    NewField = fields.get(i);
    if (field.isPrimary()) {
        if (hasPk) {
            WhereCondition.append(" and ");
        }
        //where old value
        ConditionStr = getFieldValue(OldField);
        if(ConditionStr==null){                                         WhereCondition.append("`"+field.getFieldname().toLowerCase()+"`" + " " + "is null");
        }else{
               WhereCondition.append("`"+field.getFieldname().toLowerCase()+"`"+" = "+ NewField.getValue());                      
         }
        hasPk = true;
    }
    if (hasSet) {
        SetValue.append(COMMA);
    }
      SetValue.append("`"+field.getFieldname().toLowerCase()+"`" + " = " + field.getValue());
    String setStr = getFieldValue(field);
    hasSet = true;
    }
    update_string.append("Update "+record.getTablename() +" Set " + SetValue + " Where "+WhereCondition +";");                        
}


Delete 解析


如果一个Record 是Delete语句，那么这个Record的操作类型为DELETE。下面的代码示例简单介绍当delete对应的表有主键时，如何获取完整的Delete语句： StringBuilder delete_string=new StringBuilder();                  
Record.Type type=record.getOpt();
DataMessage.Record.Field field;
StringBuilder FieldName=new StringBuilder();
StringBuilder FieldValue = new StringBuilder();
StringBuilder DeleteCondition = new StringBuilder();
boolean hasPk=false;
boolean pkMode=false;
if(type.equals(Record.Type.DELETE)){
   int i=0;
   List<DataMessage.Record.Field> fields = record.getFieldList();                    
   delete_string.append("Delete From" + record.getTablename() + "where");                        
   // 表是否有主键？
   if (record.getPrimaryKeys() != null) {
             pkMode = record.getPrimaryKeys().length() > 0 ? true : false;
   }                        
   for (; i < fields.size(); i++) {
            if ((pkMode && !field.isPrimary())) {
                    continue;
            }
            if (hasPk) {
                    delete_string.append(" and ");
            }
            delete_string.append(field.getFieldname() + "=" + field.getValue());
            hasPk = true;
    }
    delete_string.append(";");
}


Replace 解析


如果源库执行了Replace语句，那么这个Record的操作类型为UPDATE或INSERT。当replace设置的值不存在时，Record的操作类型为INSERT，当replace设置的值存在时，Record的操作类型为UPDATE。

Begin 解析


如果一个Record 是Begin语句，那么这个Record的操作类型为BEGIN。begin语句没有实际内容，所以不需要对Field做处理，只需要判断操作为begin即可,具体获取代码如下： StringBuilder sql_string = new StringBuilder();
Record.Type type = record.getOpt();
if(type.equals(Record.Type.BEGIN)){
        sql_string.append("Begin");
}


Commit 解析


如果一个Record 是Commit语句，那么这个Record的操作类型为COMMIT。commit语句没有实际内容，所以不需要对Field做处理，只需要判断操作为commit即可。 StringBuilder sql_string = new StringBuilder();
Record.Type type = record.getOpt();
if(type.equals(Record.Type.COMMIT)){
        sql_string.append("commit");
}