org.eclipse.birt.data.engine.api
Interface IResultMetaData


public interface IResultMetaData

Describes the metadata of a detail row in an IResultIterator. A detail row is defined based on a query's runtime metadata (as described by its data source driver), merging with static result set hints specified in a data set design. It includes projected columns only, which are all columns returned by a query if no explicit projection is specified. A detail row would also include any computed columns and custom columns specified in a data set design.


Method Summary
 java.lang.String getColumnAlias(int index)
          Returns the column alias at the specified index.
 int getColumnCount()
          Returns the number of columns in a detail row of the result set.
 java.lang.String getColumnLabel(int index)
          Gets the label or display name of the column at the specified index.
 java.lang.String getColumnName(int index)
          Returns the column name at the specified index.
 java.lang.String getColumnNativeTypeName(int index)
          Returns the data provider specific data type name of the specified column.
 int getColumnType(int index)
          Returns the data type of the column at the specified index.
 java.lang.String getColumnTypeName(int index)
          Returns the Data Engine data type name of the column at the specified index.
 boolean isComputedColumn(int index)
          Indicates whether the specified projected column is defined as a computed column.
 

Method Detail

getColumnCount

public int getColumnCount()
Returns the number of columns in a detail row of the result set.

Returns:
the number of columns in a detail row.

getColumnName

public java.lang.String getColumnName(int index)
                               throws BirtException
Returns the column name at the specified index.

Parameters:
index - The projected column index.
Returns:
The name of the specified column.
Throws:
BirtException - if given index is invalid.

getColumnAlias

public java.lang.String getColumnAlias(int index)
                                throws BirtException
Returns the column alias at the specified index. An alias is given to a column as a programmatic convenience. A column can be referred using a name or an alias interchangeably.

Parameters:
index - The projected column index.
Returns:
The alias of the specified column. Null if none is defined.
Throws:
BirtException - if given index is invalid.

getColumnType

public int getColumnType(int index)
                  throws BirtException
Returns the data type of the column at the specified index.

Parameters:
index - The projected column index.
Returns:
The data type of the specified column, as an integer defined in org.eclipse.birt.data.engine.api.DataType.
Throws:
BirtException - if given index is invalid.

getColumnTypeName

public java.lang.String getColumnTypeName(int index)
                                   throws BirtException
Returns the Data Engine data type name of the column at the specified index.

Parameters:
index - The projected column index.
Returns:
The Data Engine data type name of the specified column.
Throws:
BirtException - if given index is invalid.

getColumnNativeTypeName

public java.lang.String getColumnNativeTypeName(int index)
                                         throws BirtException
Returns the data provider specific data type name of the specified column.

Returns:
the data type name as defined by the data provider.
Throws:
BirtException - if given index is invalid.

getColumnLabel

public java.lang.String getColumnLabel(int index)
                                throws BirtException
Gets the label or display name of the column at the specified index.

Parameters:
index - The projected column index.
Returns:
The label of the specified column.
Throws:
BirtException - if given index is invalid.

isComputedColumn

public boolean isComputedColumn(int index)
                         throws BirtException
Indicates whether the specified projected column is defined as a computed column. A computed column is one that is not retrieved from the underlying data provider. Only those computed columns declared explicitly in a data set design are considered as "computed" columns.

Parameters:
index - The projected column index.
Returns:
true if the given column is a computed column; false otherwise.
Throws:
BirtException - if given index is invalid.


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