Data type column size does not match size of values returned

Question

I've tried searching but couldn't find what I was looking for, sorry if this has been answered or is a duplicate.
I am using the (Java) method below to get the column definitions of a table. I am doing this through an ODBC connection (using Oracle ODBC driver) and I have NO CHOICE in the matter.
The problem I am having is that one particular column has a column size is smaller than the size of the data it purportedly holds (ie attendance_code = varchar size 3 but data value is "Absent". I suspect the data is actually a look up to situation, where my attendance_code column has a value of 'ABS' and Oracle goes and fetchs the "Absent" value.
My issue is that the meta data returned from ODBC is the actual column definition (ie varchar(3) and not varchar2(10) for example).
The resultset metadata has a size of 3 for the column in question, and querying the schema also yields 3 for that column.
How do I resolve this? I do not have access to all_columns table etc. I have to do it using ODBC metadata only.
I've tried recreating the situation using the Oracle XE DB, but as I am not familiar with Oracle, I do not know how to recreate this scenario (which would then lead me to test other options with ODBC).
TIA.
The select I am using is SELECT * FROM <tableName>.
public ArrayList<SchemaColumn> getColumnsForTable(String catalog,
String schema,
String tableName) {
ArrayList<SchemaColumn> columns = new ArrayList<SchemaColumn>();
ResultSet rs = null;
try {
DatabaseMetaData metaData = connection.getMetaData();
rs = metaData.getColumns(catalog, schema, tableName, "%");
SchemaColumn column;
while (rs.next()) {
column = new SchemaColumn();
column.setName(rs.getString("COLUMN_NAME"));
column.setDataType(rs.getInt("DATA_TYPE"));
column.setTypeName(rs.getString("TYPE_NAME"));
column.setColumnSize(rs.getInt("COLUMN_SIZE")); <-------- this is the value that is coming back smaller than the data it actually returns
column.setDecimalDigits(rs.getInt("DECIMAL_DIGITS"));
column.setNumPrecisionRadix(rs.getInt("NUM_PREC_RADIX"));
column.setNullable(rs.getInt("NULLABLE"));
column.setRemarks(rs.getString("REMARKS"));
column.setDefaultValue(rs.getString("COLUMN_DEF"));
column.setSqlDataType(rs.getInt("SQL_DATA_TYPE"));
column.setSqlDateTimeSub(rs.getInt("SQL_DATETIME_SUB"));
column.setCharOctetLength(rs.getInt("CHAR_OCTET_LENGTH"));
column.setOrdinalPosition(rs.getInt("ORDINAL_POSITION"));
columns.add(column);
} catch (Exception e) {
Log.getLogger().error("Could not capture table schema");
closeResultSet(rs);
return columns;
}

Answer 1

I can't say I've ever seen a case where a column held more data than it was declared as, and would have to file that under "see it to believe it" category.
Even if that somehow were the case, I'd expect the ODBC driver to return what the column is defined as anyway, not the data. The data changes with every row, but I'd expect the table metadata to be consistent, and refer to the table definition.
For grins though, can you provide system.out.println output of the metadata, and also a "describe xxxx" from sqlplus if you can, where xxx is the table name?
ie,
while (rs.next()) {
System.out.println("column name is " + rs.getString("COLUMN_NAME"));
System.out.println("data type is " + rs.getInt("DATA_TYPE"));
..etc..
Greg