在将数据插入到SQL for DB2的表中之前，如何对列的值进行大小验证？

Question

I need to check whether the value is with proper size to be inserted into a table for particular column before actual insertion of data into table.

eg,

Suppose, I have a table 'MyTable' with column 'MYSMALLINT' of SMALLINT type in DB2,

If I try to insert the value as,

insert into MyTable(MYSMALLINT) values(12222222222222222222222222222225552);

I will get below error, after executing the above query:

Message: The numeric literal "12222222222222222222222222222225552" is not valid because its value is out of range.

Here, I need to check the size of value before inserting the data into table in Java/JDBC for a column with any data type(CHAR,VARCHAR,INT,BIGINT,TINYINT,DOUBLE,FLOAT,DECIMAL,REAL,...).

Answer 1

You can do it with PreparedStatement :

PreparedStatement statement = connection.prepareStatement("insert into MyTable(MYSMALLINT) values(?);"
for(Integer value:values){
   try{
      statement.setInt(1,value);
      statement.addBatch();
   }catch(SQLException e){
      System.err.println("Invalid value: " + e.getMessage());
      throw e;
   }
}
statement.executeBatch();

Answer 2

You can validate the before value in a trigger if it is valid for your requirements. The way you validate the value can a UDF, in that way you can test it outside the trigger.

Answer 3

Why not just map the column to the correct Java primitive.

Smallint is equivalent to a "short" in Java so if you defined your host variable as a short the compiler would detect any errors at compile time.

insert into MyTable(MYSMALLINT) values(12222222222222222222222222222225552S);

would be spat out by your java compiler.