Class AccessDatabase

java.lang.Object

org.apache.derby.impl.tools.planexporter.AccessDatabase

public class AccessDatabase
extends Object

This class will perform the database connection establishment, querying the database, shut downing the database. Created under DERBY-4587-PlanExporter tool

Field Summary

Fields

Modifier and Type	Field	Description
private final Connection	conn
private TreeNode[]	data
private int	depth
private static final int	ID
private static final int	INPUT_ROWS
private static final int	NEXT_QUALIFIERS
private static final int	NO_OF_OPENS
private static final int	NO_OF_OUTPUT_ROWS_BY_SORTER
private static final int	NODE_TYPE
private static final int	P_ID
private final String	query
private static final int	RETURNED_ROWS
private static final int	SCAN_QUALIFIERS
private static final int	SCAN_TYPE
private static final int	SCANNED_OBJECT
private final String	schema
private final boolean	schemaExists
private static final int	SORT_TYPE
private static final int	VISITED_PAGES
private String	xmlDetails

Constructor Summary

Constructors

Constructor	Description
AccessDatabase(String dburl, String aSchema, String aQuery)
AccessDatabase(Connection aConn, String aSchema, String aQuery)

Method Summary

Modifier and Type	Method	Description
void	closeConnection()	closing the connection to the database
private static Connection	createConnection(String dbURL)
private void	createXMLData(String qry, int x)	Create XML data based on the query that's passed in.
void	createXMLFragment()	This method creates the queries such that after execution of the query it will return XML data fragments.
private static String	escapeForXML(String text)	Escape characters that have a special meaning in XML.
private String	escapeInAttribute(String text)	This method is needed since in the case of XML attributes we have to filter the quotation (") marks that is compulsory. eg: scanned_object="A "quoted" table name";
private void	findChildren(int idx, int dep)
private void	getChildren(int currentLevel, String id)
TreeNode[]	getData()
int	getDepth()
String	getQuery()
String	getXmlString()	Generating the XML tree
String	indent(int j)
boolean	initializeDataArray()
void	markTheDepth()	marking the depth of each element
private int	noOfNodes()
private boolean	schemaExists()	Check if there is a schema in the database that matches the schema name that was passed in to this instance.
private void	setSchema()	Set the schema of the current connection to the XPLAIN schema in which the statistics can be found.
String	statement()
String	stmtID()
String	time()
boolean	verifySchemaExistance()

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

conn

private final Connection conn

schema

private final String schema

query

private final String query

schemaExists

private final boolean schemaExists

data

private TreeNode[] data

depth

private int depth

xmlDetails

private String xmlDetails

ID

private static final int ID

See Also:

• Constant Field Values

P_ID

private static final int P_ID

See Also:

• Constant Field Values

NODE_TYPE

private static final int NODE_TYPE

See Also:

• Constant Field Values

NO_OF_OPENS

private static final int NO_OF_OPENS

See Also:

• Constant Field Values

INPUT_ROWS

private static final int INPUT_ROWS

See Also:

• Constant Field Values

RETURNED_ROWS

private static final int RETURNED_ROWS

See Also:

• Constant Field Values

VISITED_PAGES

private static final int VISITED_PAGES

See Also:

• Constant Field Values

SCAN_QUALIFIERS

private static final int SCAN_QUALIFIERS

See Also:

• Constant Field Values

NEXT_QUALIFIERS

private static final int NEXT_QUALIFIERS

See Also:

• Constant Field Values

SCANNED_OBJECT

private static final int SCANNED_OBJECT

See Also:

• Constant Field Values

SCAN_TYPE

private static final int SCAN_TYPE

See Also:

• Constant Field Values

SORT_TYPE

private static final int SORT_TYPE

See Also:

• Constant Field Values

NO_OF_OUTPUT_ROWS_BY_SORTER

private static final int NO_OF_OUTPUT_ROWS_BY_SORTER

See Also:

• Constant Field Values

Constructor Details

AccessDatabase

public AccessDatabase(String dburl,
 String aSchema,
 String aQuery)
               throws InstantiationException,
IllegalAccessException,
ClassNotFoundException,
SQLException,
NoSuchMethodException,
InvocationTargetException

Parameters:

dburl -

aSchema -

aQuery -

Throws:

InstantiationException

IllegalAccessException

ClassNotFoundException

SQLException

NoSuchMethodException

InvocationTargetException

AccessDatabase

public AccessDatabase(Connection aConn,
 String aSchema,
 String aQuery)
               throws SQLException

Parameters:

aConn -

aSchema -

aQuery -

Throws:

SQLException

Method Details

getQuery

public String getQuery()

Returns:

the stmt_id

getDepth

public int getDepth()

createConnection

private static Connection createConnection(String dbURL)
                                    throws InstantiationException,
IllegalAccessException,
ClassNotFoundException,
SQLException,
NoSuchMethodException,
InvocationTargetException

Throws:

InstantiationException

IllegalAccessException

ClassNotFoundException

SQLException

NoSuchMethodException

InvocationTargetException

setSchema

private void setSchema()
                throws SQLException

Set the schema of the current connection to the XPLAIN schema in which the statistics can be found.

Throws:

SQLException - if an error happens while accessing the database

schemaExists

private boolean schemaExists()
                      throws SQLException

Check if there is a schema in the database that matches the schema name that was passed in to this instance.

Throws:

SQLException

verifySchemaExistance

public boolean verifySchemaExistance()

createXMLFragment

public void createXMLFragment()
                       throws SQLException

This method creates the queries such that after execution of the query it will return XML data fragments.

Throws:

SQLException

getXmlString

public String getXmlString()

Generating the XML tree

Returns:

all xml elements as a String

getChildren

private void getChildren(int currentLevel,
 String id)

Parameters:

currentLevel - level of the XML tree (0 based) of current node

id - current node's stmt_id

indent

public String indent(int j)

Parameters:

j - indent needed

Returns:

indent as a string

markTheDepth

public void markTheDepth()

marking the depth of each element

findChildren

private void findChildren(int idx,
 int dep)

Parameters:

idx - current element's index

dep - current examining depth

initializeDataArray

public boolean initializeDataArray()
                            throws SQLException

Returns:

whether the initialization is successful or not

Throws:

SQLException

createXMLData

private void createXMLData(String qry,
 int x)
                    throws SQLException

Create XML data based on the query that's passed in. The query should have exactly one parameter, which will be initialized to the statement id before the query is executed.

Parameters:

qry - query to be executed

Throws:

SQLException

noOfNodes

private int noOfNodes()
               throws SQLException

Returns:

total # of nodes

Throws:

SQLException

statement

public String statement()
                 throws SQLException

Returns:

the <statement> element

Throws:

SQLException

escapeForXML

private static String escapeForXML(String text)

Escape characters that have a special meaning in XML.

Parameters:

text - the text to escape

Returns:

the text with special characters escaped

escapeInAttribute

private String escapeInAttribute(String text)

This method is needed since in the case of XML attributes we have to filter the quotation (") marks that is compulsory. eg: scanned_object="A "quoted" table name";

Parameters:

text - attribute string to be checked

Returns:

modified string

time

public String time()
            throws SQLException

Returns:

XPLAIN_TIME of SYSXPLAIN_STATEMENTS

Throws:

SQLException

stmtID

public String stmtID()

Returns:

stmt_id as a XML element

closeConnection

public void closeConnection()

closing the connection to the database

getData

public TreeNode[] getData()

Returns:

data array of TreeNode Objects