Package org.apache.derby.iapi.sql
Interface ResultDescription
- All Known Implementing Classes:
GenericResultDescription
public interface ResultDescription
The ResultDescription interface provides methods to get metadata on the
results returned by a statement.
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Method Summary
Modifier and TypeMethodDescriptionint
findColumnInsenstive
(String name) Return the position of the column matching the passed in names following the JDBC rules for ResultSet.getXXX and updateXXX.int
Returns the number of columns in the result set.getColumnDescriptor
(int position) Returns a ResultColumnDescriptor for the column, given the ordiinal position of the column.Return information about all the columns.getColumnInfo
(int idx) Return the information about a single column (0-based indexing)Get the saved JDBC ResultSetMetaData.Returns an identifier that tells what type of statement has been executed.void
setMetaData
(ResultSetMetaData rsmd) Set the JDBC ResultSetMetaData for this ResultDescription.truncateColumns
(int truncateFrom) Get a new result description that has been truncated from input column number.
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Method Details
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getStatementType
String getStatementType()Returns an identifier that tells what type of statement has been executed. This can be used to determine what other methods to call to get the results back from a statement. For example, a SELECT statement returns rows and columns, while other statements don't, so you would only call getColumnCount() or getColumnType() for SELECT statements.- Returns:
- A String identifier telling what type of statement this is.
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getColumnCount
int getColumnCount()Returns the number of columns in the result set.- Returns:
- The number of columns in the result set.
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getColumnInfo
ResultColumnDescriptor[] getColumnInfo()Return information about all the columns. -
getColumnInfo
Return the information about a single column (0-based indexing) -
getColumnDescriptor
Returns a ResultColumnDescriptor for the column, given the ordiinal position of the column. NOTE - position is 1-based.- Parameters:
position
- The oridinal position of a column in the ResultSet.- Returns:
- A ResultColumnDescriptor describing the column in the ResultSet.
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truncateColumns
Get a new result description that has been truncated from input column number. If the input column is 5, then columns 5 to getColumnCount() are removed. The new ResultDescription points to the same ColumnDescriptors (this method performs a shallow copy. The saved JDBC ResultSetMetaData will not be copied.- Parameters:
truncateFrom
- the starting column to remove, 1-based.- Returns:
- a new ResultDescription
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setMetaData
Set the JDBC ResultSetMetaData for this ResultDescription. A ResultSetMetaData object can be saved in the statement plan using this method. This only works while the ResultSetMetaData api does not contain a getConnection() method or a close method.
If this object already has a saved meta data object this call will do nothing. Due to synchronization the saved ResultSetMetaData object may not be the one passed in, ie. if two threads call this concurrently, only one will be saved. It is assumed the JDBC layer passes in a ResultSetMetaData object based upon this. -
getMetaData
ResultSetMetaData getMetaData()Get the saved JDBC ResultSetMetaData. Will return null if setMetaData() has not been called on this object. The caller then should manufacture a ResultSetMetaData object and pass it into setMetaData. -
findColumnInsenstive
Return the position of the column matching the passed in names following the JDBC rules for ResultSet.getXXX and updateXXX. Rules are the matching is case insensitive and the insensitive name matches the first column found that matches (starting at postion 1).- Parameters:
name
-- Returns:
- Position of the column (1-based), -1 if no match.
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