org.h2.fulltext

Class FullText

java.lang.Object

org.h2.fulltext.FullText

Direct Known Subclasses:

FullTextLucene

public class FullText
extends Object

This class implements the native full text search. Most methods can be called using SQL statements as well.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	FullText.FullTextTrigger Trigger updates the index when a inserting, updating, or deleting a row.

Constructor Summary

Constructors

Constructor and Description
FullText()

Method Summary

Methods

Modifier and Type	Method and Description
protected static void	addWords(FullTextSettings setting, HashSet<String> set, Reader reader) Add all words in the given text to the hash set.
protected static void	addWords(FullTextSettings setting, HashSet<String> set, String text) Add all words in the given text to the hash set.
protected static String	asString(Object data, int type) INTERNAL.
static void	closeAll() INTERNAL Close all fulltext settings, freeing up memory.
static void	createIndex(Connection conn, String schema, String table, String columnList) Create a new full text index for a table and column list.
protected static SimpleResultSet	createResultSet(boolean data) Create an empty search result and initialize the columns.
protected static void	createTrigger(Connection conn, String schema, String table) Create the trigger.
static void	dropAll(Connection conn) Drops all full text indexes from the database.
static void	dropIndex(Connection conn, String schema, String table) Drop an existing full text index for a table.
protected static boolean	hasChanged(Object[] oldRow, Object[] newRow, int[] indexColumns) Check if a the indexed columns of a row probably have changed.
protected static void	indexExistingRows(Connection conn, String schema, String table) Add the existing data to the index.
static void	init(Connection conn) Initializes full text search functionality for this database.
protected static Object[][]	parseKey(Connection conn, String key) Parse a primary key condition into the primary key columns.
protected static String	quoteSQL(Object data, int type) INTERNAL.
static void	reindex(Connection conn) Re-creates the full text index for this database.
protected static void	removeAllTriggers(Connection conn, String prefix) Remove all triggers that start with the given prefix.
static ResultSet	search(Connection conn, String text, int limit, int offset) Searches from the full text index for this database.
protected static ResultSet	search(Connection conn, String text, int limit, int offset, boolean data) Do the search.
static ResultSet	searchData(Connection conn, String text, int limit, int offset) Searches from the full text index for this database.
protected static void	setColumns(int[] index, ArrayList<String> keys, ArrayList<String> columns) Set the column indices of a set of keys.
static void	setIgnoreList(Connection conn, String commaSeparatedList) Change the ignore list.
static void	setWhitespaceChars(Connection conn, String whitespaceChars) Change the whitespace characters.
protected static SQLException	throwException(String message) Throw a SQLException with the given message.

Methods inherited from class java.lang.Object

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

Constructor Detail

FullText

public FullText()

Method Detail

init

public static void init(Connection conn)
                 throws SQLException

Initializes full text search functionality for this database. This adds the following Java functions to the database:

• FT_CREATE_INDEX(schemaNameString, tableNameString, columnListString)
• FT_SEARCH(queryString, limitInt, offsetInt): result set
• FT_REINDEX()
• FT_DROP_ALL()

It also adds a schema FT to the database where bookkeeping information is stored. This function may be called from a Java application, or by using the SQL statements:

 CREATE ALIAS IF NOT EXISTS FT_INIT FOR
      "org.h2.fulltext.FullText.init";
 CALL FT_INIT();
 

Parameters:

conn - the connection

Throws:

SQLException

createIndex

public static void createIndex(Connection conn,
               String schema,
               String table,
               String columnList)
                        throws SQLException

Create a new full text index for a table and column list. Each table may only have one index at any time.

Parameters:

conn - the connection

schema - the schema name of the table (case sensitive)

table - the table name (case sensitive)

columnList - the column list (null for all columns)

Throws:

SQLException

reindex

public static void reindex(Connection conn)
                    throws SQLException

Re-creates the full text index for this database. Calling this method is usually not needed, as the index is kept up-to-date automatically.

Parameters:

conn - the connection

Throws:

SQLException

dropIndex

public static void dropIndex(Connection conn,
             String schema,
             String table)
                      throws SQLException

Drop an existing full text index for a table. This method returns silently if no index for this table exists.

Parameters:

conn - the connection

schema - the schema name of the table (case sensitive)

table - the table name (case sensitive)

Throws:

SQLException

dropAll

public static void dropAll(Connection conn)
                    throws SQLException

Drops all full text indexes from the database.

Parameters:

conn - the connection

Throws:

SQLException

search

public static ResultSet search(Connection conn,
               String text,
               int limit,
               int offset)
                        throws SQLException

Searches from the full text index for this database. The returned result set has the following column:

• QUERY (varchar): the query to use to get the data. The query does not include 'SELECT * FROM '. Example: PUBLIC.TEST WHERE ID = 1
• SCORE (float) the relevance score. This value is always 1.0 for the native fulltext search.

Parameters:

conn - the connection

text - the search query

limit - the maximum number of rows or 0 for no limit

offset - the offset or 0 for no offset

Returns:

the result set

Throws:

SQLException

searchData

public static ResultSet searchData(Connection conn,
                   String text,
                   int limit,
                   int offset)
                            throws SQLException

Searches from the full text index for this database. The result contains the primary key data as an array. The returned result set has the following columns:

• SCHEMA (varchar): the schema name. Example: PUBLIC
• TABLE (varchar): the table name. Example: TEST
• COLUMNS (array of varchar): comma separated list of quoted column names. The column names are quoted if necessary. Example: (ID)
• KEYS (array of values): comma separated list of values. Example: (1)
• SCORE (float) the relevance score. This value is always 1.0 for the native fulltext search.

Parameters:

conn - the connection

text - the search query

limit - the maximum number of rows or 0 for no limit

offset - the offset or 0 for no offset

Returns:

the result set

Throws:

SQLException

setIgnoreList

public static void setIgnoreList(Connection conn,
                 String commaSeparatedList)
                          throws SQLException

Change the ignore list. The ignore list is a comma separated list of common words that must not be indexed. The default ignore list is empty. If indexes already exist at the time this list is changed, reindex must be called.

Parameters:

conn - the connection

commaSeparatedList - the list

Throws:

SQLException

setWhitespaceChars

public static void setWhitespaceChars(Connection conn,
                      String whitespaceChars)
                               throws SQLException

Change the whitespace characters. The whitespace characters are used to separate words. If indexes already exist at the time this list is changed, reindex must be called.

Parameters:

conn - the connection

whitespaceChars - the list of characters

Throws:

SQLException

asString

protected static String asString(Object data,
              int type)
                          throws SQLException

INTERNAL. Convert the object to a string.

Parameters:

data - the object

type - the SQL type

Returns:

the string

Throws:

SQLException

createResultSet

protected static SimpleResultSet createResultSet(boolean data)

Create an empty search result and initialize the columns.

Parameters:

data - true if the result set should contain the primary key data as an array.

Returns:

the empty result set

parseKey

protected static Object[][] parseKey(Connection conn,
                  String key)

Parse a primary key condition into the primary key columns.

Parameters:

conn - the database connection

key - the primary key condition as a string

Returns:

an array containing the column name list and the data list

quoteSQL

protected static String quoteSQL(Object data,
              int type)
                          throws SQLException

INTERNAL. Convert an object to a String as used in a SQL statement.

Parameters:

data - the object

type - the SQL type

Returns:

the SQL String

Throws:

SQLException

removeAllTriggers

protected static void removeAllTriggers(Connection conn,
                     String prefix)
                                 throws SQLException

Remove all triggers that start with the given prefix.

Parameters:

conn - the database connection

prefix - the prefix

Throws:

SQLException

setColumns

protected static void setColumns(int[] index,
              ArrayList<String> keys,
              ArrayList<String> columns)
                          throws SQLException

Set the column indices of a set of keys.

Parameters:

index - the column indices (will be modified)

keys - the key list

columns - the column list

Throws:

SQLException

search

protected static ResultSet search(Connection conn,
               String text,
               int limit,
               int offset,
               boolean data)
                           throws SQLException

Do the search.

Parameters:

conn - the database connection

text - the query

limit - the limit

offset - the offset

data - whether the raw data should be returned

Returns:

the result set

Throws:

SQLException

addWords

protected static void addWords(FullTextSettings setting,
            HashSet<String> set,
            Reader reader)

Add all words in the given text to the hash set.

Parameters:

setting - the fulltext settings

set - the hash set

reader - the reader

addWords

protected static void addWords(FullTextSettings setting,
            HashSet<String> set,
            String text)

Add all words in the given text to the hash set.

Parameters:

setting - the fulltext settings

set - the hash set

text - the text

createTrigger

protected static void createTrigger(Connection conn,
                 String schema,
                 String table)
                             throws SQLException

Create the trigger.

Parameters:

conn - the database connection

schema - the schema name

table - the table name

Throws:

SQLException

indexExistingRows

protected static void indexExistingRows(Connection conn,
                     String schema,
                     String table)
                                 throws SQLException

Add the existing data to the index.

Parameters:

conn - the database connection

schema - the schema name

table - the table name

Throws:

SQLException

hasChanged

protected static boolean hasChanged(Object[] oldRow,
                 Object[] newRow,
                 int[] indexColumns)

Check if a the indexed columns of a row probably have changed. It may return true even if the change was minimal (for example from 0.0 to 0.00).

Parameters:

oldRow - the old row

newRow - the new row

indexColumns - the indexed columns

Returns:

true if the indexed columns don't match

closeAll

public static void closeAll()

INTERNAL Close all fulltext settings, freeing up memory.

throwException

protected static SQLException throwException(String message)
                                      throws SQLException

Throw a SQLException with the given message.

Parameters:

message - the message

Returns:

never returns normally

Throws:

SQLException - the exception