Subject Re: [Firebird-Java] Additional metadata from ResultSet
Author Mark Rotteveel
On 10-1-2018 12:26, hugo.larson@... [Firebird-Java] wrote:
> The Jaybird Class FieldDescriptor contains very interesting information.
> FieldDescriptor:[Position=29,FieldName=ID_PC,TableAlias=PC,Type=501,SubType=0,Scale=0,Length=2,OriginalName=ID,OriginalTableName=PRODUCTCATEGORY,OwnerName=SYSDBA]
> Is it possible to access these values from ResultsetMetadata?

Most of them:

- Position is the 0-based position of the column (JDBC itself uses
1-based positions), so you already have this information when accessing
columns in `ResultSetMetaData`

- FieldName is `getColumnLabel` (unless FieldName is null, then it is

- TableAlias is `getTableAlias` (defined in `FirebirdResultSetMetaData`)

- Type, SubType and Scale is translated to the appropriate JDBC type,
and can - partially - be retrieved using `getColumnTypeName`

- The nullable bit of Type can be retrieved using `isNullable` (500
means it is a SMALLINT NOT NULL, and 501 means that it is a nullable

- Type and SubType are not directly retrievable

- Scale can be retrieved using `getScale` (contrary to the requirements
of JDBC, Jaybird currently always returns scale, this may change in the

- Length is the number of bytes of a column (8 for blobs), it is not
immediately accessible (but is used to derive `getColumnDisplaySize` and
`getPrecision` for (var)char columns

- OriginalName is `getColumnName` (except when connection property
columnLabelForName is set, then it returns the same as `getColumnLabel`)

- OriginalTableName is `getTableName` (might not always be available, eg
calculated values, UNION selects)

Mark Rotteveel