Class H2Dialect

Object
SQLDialect
H2Dialect

public class H2Dialect extends SQLDialect
Delegate for H2DialectBasic and H2DialectPrepared which implements the common parts of the dialect api.
Author:
Justin Deoliveira, OpenGEO
  • Field Details

    • H2_SPATIAL_INDEX

      public static String H2_SPATIAL_INDEX
  • Constructor Details

  • Method Details

    • getNameEscape

      public String getNameEscape()
      Description copied from class: SQLDialect
      Returns the string used to escape names.

      This value is used to escape any name in a query. This includes columns, tables, schemas, indexes, etc... If no escape is necessary this method should return the empty string, and never return null.

      This default implementation returns a single double quote ("), subclasses must override to provide a different espcape.

      Overrides:
      getNameEscape in class SQLDialect
    • initializeConnection

      public void initializeConnection(Connection cx) throws SQLException
      Description copied from class: SQLDialect
      Initializes a newly created database connection.

      Subclasses should override this method if there is some additional action that needs to be taken when a new connection to the database is created. The default implementation does nothing.

      Overrides:
      initializeConnection in class SQLDialect
      Parameters:
      cx - The new database connection.
      Throws:
      SQLException
    • includeTable

      public boolean includeTable(String schemaName, String tableName, Connection cx) throws SQLException
      Description copied from class: SQLDialect
      Determines if the specified table should be included in those published by the datastore.

      This method returns true if the table should be published as a feature type, otherwise it returns false. Subclasses should override this method, this default implementation returns true.

      A database connection is provided to the dialect but it should not be closed. However any statements objects or result sets that are instantiated from it must be closed.

      Overrides:
      includeTable in class SQLDialect
      Parameters:
      schemaName - The schema of the table, might be null..
      tableName - The name of the table.
      cx - Database connection.
      Throws:
      SQLException
    • getMapping

      public Class<?> getMapping(ResultSet columnMetaData, Connection cx) throws SQLException
      Description copied from class: SQLDialect
      Determines the class mapping for a particular column of a table.

      Implementing this method is optional. It is used to allow database to perform custom type mappings based on various column metadata. It is called before the mappings registered in SQLDialect.registerSqlTypeToClassMappings(Map) and are used to determine the mapping. Subclasses should implement as needed, this default implementation returns <code>null</code>. </p> <p> The <tt>columnMetaData</tt> argument is provided from {@link DatabaseMetaData#getColumns(String, String, String, String)}. </p>

      Overrides:
      getMapping in class SQLDialect
      Parameters:
      columnMetaData - The column metadata
      cx - The connection used to retrieve the metadata
      Returns:
      The class mapped to the to column, or null.
      Throws:
      SQLException
    • encodePostColumnCreateTable

      public void encodePostColumnCreateTable(AttributeDescriptor att, StringBuffer sql)
      Description copied from class: SQLDialect
      Encodes anything post a column in a CREATE TABLE statement.

      This is appended after the column name and type. Subclasses may choose to override this method, the default implementation does nothing.

      Overrides:
      encodePostColumnCreateTable in class SQLDialect
      Parameters:
      att - The attribute corresponding to the column.
    • registerSqlTypeToClassMappings

      public void registerSqlTypeToClassMappings(Map<Integer,Class<?>> mappings)
      Description copied from class: SQLDialect
      Registers the sql type to java type mappings that the dialect uses when reading and writing objects to and from the database.

      Subclasses should extend (not override) this method to provide additional mappings, or to override mappings provided by this implementation. This implementation provides the following mappings:

      Overrides:
      registerSqlTypeToClassMappings in class SQLDialect
    • registerClassToSqlMappings

      public void registerClassToSqlMappings(Map<Class<?>,Integer> mappings)
      Description copied from class: SQLDialect
      Registers the java type to sql type mappings that the datastore uses when reading and writing objects to and from the database. *

      Subclasses should extend (not override) this method to provide additional mappings, or to override mappings provided by this implementation. This implementation provides the following mappings:

      Overrides:
      registerClassToSqlMappings in class SQLDialect
    • postCreateTable

      public void postCreateTable(String schemaName, SimpleFeatureType featureType, Connection cx) throws SQLException
      Description copied from class: SQLDialect
      Callback to execute any additional sql statements post a create table statement.

      This method should be implemented by subclasses that need to do some post processing on the database after a table has been created. Examples might include:

      • Creating a sequence for a primary key
      • Registering geometry column metadata
      • Creating a spatial index

      A common case is creating an auto incrementing sequence for the primary key of a table. It should be noted that all tables created through the datastore use the column "fid" as the primary key.

      A direct connection to the database is provided (cx). This connection must not be closed, however any statements or result sets instantiated from the connection must be closed.

      Overrides:
      postCreateTable in class SQLDialect
      Parameters:
      schemaName - The name of the schema, may be null.
      featureType - The feature type that has just been created on the database.
      cx - Database connection.
      Throws:
      SQLException
    • postCreateFeatureType

      public void postCreateFeatureType(SimpleFeatureType featureType, DatabaseMetaData metadata, String schemaName, Connection cx) throws SQLException
      Description copied from class: SQLDialect
      Callback which executes after a feature type has been built from a database table.

      This base implementation does nothing, subclasses should override as need be.

      Overrides:
      postCreateFeatureType in class SQLDialect
      Parameters:
      featureType - The build feature type.
      metadata - The database metadata.
      schemaName - The name of the database scheam containing the table containing the column
      cx - The database connection.
      Throws:
      SQLException
    • preDropTable

      public void preDropTable(String schemaName, SimpleFeatureType featureType, Connection cx) throws SQLException
      Description copied from class: SQLDialect
      Callback which executes before a table is about to be dropped.

      This base implementation does nothing, subclasses should override as need be.

      Overrides:
      preDropTable in class SQLDialect
      Parameters:
      schemaName - The database schema containing the table.
      featureType - The featureType/table being dropped.
      cx - The database connection.
      Throws:
      SQLException
    • getGeometrySRID

      public Integer getGeometrySRID(String schemaName, String tableName, String columnName, Connection cx) throws SQLException
      Description copied from class: SQLDialect
      Returns the spatial reference system identifier (srid) for a particular geometry column.

      This method is given a direct connection to the database. The connection must not be closed. However any statements or result sets instantiated from the connection must be closed.

      In the event that the srid cannot be determined, this method should return null .

      Overrides:
      getGeometrySRID in class SQLDialect
      Parameters:
      schemaName - The database schema, could be null.
      tableName - The table, never null.
      columnName - The column name, never null
      cx - The database connection.
      Throws:
      SQLException
    • encodeGeometryEnvelope

      public void encodeGeometryEnvelope(String tableName, String geometryColumn, StringBuffer sql)
      Description copied from class: SQLDialect
      Encodes the spatial extent function of a geometry column in a SELECT statement.

      This method must also be sure to properly encode the name of the column with the #encodeColumnName(String, StringBuffer) function.

      Specified by:
      encodeGeometryEnvelope in class SQLDialect
    • decodeGeometryEnvelope

      public Envelope decodeGeometryEnvelope(ResultSet rs, int column, Connection cx) throws SQLException, IOException
      Description copied from class: SQLDialect
      Decodes the result of a spatial extent function in a SELECT statement.

      This method is given direct access to a result set. The column parameter is the index into the result set which contains the spatial extent value. The query for this value is build with the SQLDialect.encodeGeometryEnvelope(String, String, StringBuffer) method.

      This method must not read any other objects from the result set other then the one referenced by column.

      Specified by:
      decodeGeometryEnvelope in class SQLDialect
      Parameters:
      rs - A result set
      column - Index into the result set which points at the spatial extent value.
      cx - The database connection.
      Throws:
      SQLException
      IOException
    • encodeGeometryValue

      public void encodeGeometryValue(Geometry value, int srid, StringBuffer sql) throws IOException
      Throws:
      IOException
    • decodeGeometryValue

      public Geometry decodeGeometryValue(GeometryDescriptor descriptor, ResultSet rs, String column, GeometryFactory factory, Connection cx, Hints hints) throws IOException, SQLException
      Description copied from class: SQLDialect
      Decodes a geometry value from the result of a query.

      This method is given direct access to a result set. The column parameter is the index into the result set which contains the geometric value.

      An implementation should deserialize the value provided by the result set into Geometry object. For example, consider an implementation which deserializes from well known text:

         String wkt = rs.getString( column );
         if ( wkt == null ) {
           return null;
         }
         return new WKTReader(factory).read( wkt );
         
      Note that implementations must handle null values.

      The factory parameter should be used to instantiate any geometry objects.

      Specified by:
      decodeGeometryValue in class SQLDialect
      Throws:
      IOException
      SQLException
    • encodePrimaryKey

      public void encodePrimaryKey(String column, StringBuffer sql)
      Description copied from class: SQLDialect
      Encodes the primary key definition in a CREATE TABLE statement.

      Subclasses should override this method if need be, the default implementation does the following:

         
         encodeColumnName( column, sql );
         sql.append( " int PRIMARY KEY" );
         
       
      Overrides:
      encodePrimaryKey in class SQLDialect
    • getSequenceForColumn

      public String getSequenceForColumn(String schemaName, String tableName, String columnName, Connection cx) throws SQLException
      Description copied from class: SQLDialect
      Determines the name of the sequence (if any) which is used to increment generate values for a table column.

      This method should return null if no such sequence exists.

      This method is given a direct connection to the database, but this connection should never be closed. However any statements or result sets instantiated from the connection must be closed.

      Overrides:
      getSequenceForColumn in class SQLDialect
      Parameters:
      schemaName - The schema name, this might be null.
      tableName - The table name.
      columnName - The column name.
      cx - The database connection.
      Throws:
      SQLException
    • getNextSequenceValue

      public Object getNextSequenceValue(String schemaName, String sequenceName, Connection cx) throws SQLException
      Description copied from class: SQLDialect
      Obtains the next value of a sequence, incrementing the sequence to the next state in the process.

      Implementations should determine the next value of a column for which values are automatically generated by the database.

      This method is given a direct connection to the database, but this connection should never be closed. However any statements or result sets instantiated from the connection must be closed.

      Implementations should handle the case where schemaName is null.

      Overrides:
      getNextSequenceValue in class SQLDialect
      Parameters:
      schemaName - The schema name, this might be null.
      sequenceName - The name of the sequence.
      cx - The database connection.
      Returns:
      The next value of the sequence, or null.
      Throws:
      SQLException
    • encodeNextSequenceValue

      public String encodeNextSequenceValue(String schemaName, String sequenceName)
      Description copied from class: SQLDialect
      Encodes how to get the next sequence value from the DB.

      Implementations should handle the case where schemaName is null.

      Overrides:
      encodeNextSequenceValue in class SQLDialect
    • getNextAutoGeneratedValue

      public Object getNextAutoGeneratedValue(String schemaName, String tableName, String columnName, Connection cx) throws SQLException
      Description copied from class: SQLDialect
      Obtains the next value of an auto generated column.

      Implementations should determine the next value of a column for which values are automatically generated by the database.

      This method is given a direct connection to the database, but this connection should never be closed. However any statements or result sets instantiated from the connection must be closed.

      Implementations should handle the case where schemaName is null.

      Overrides:
      getNextAutoGeneratedValue in class SQLDialect
      Parameters:
      schemaName - The schema name, this might be null.
      tableName - The name of the table.
      columnName - The column.
      cx - The database connection.
      Returns:
      The next value of the column, or null.
      Throws:
      SQLException
    • isLimitOffsetSupported

      public boolean isLimitOffsetSupported()
      Description copied from class: SQLDialect
      Returns true if this dialect can encode both Query.getStartIndex() and Query.getMaxFeatures() into native SQL.
      Overrides:
      isLimitOffsetSupported in class SQLDialect
    • applyLimitOffset

      public void applyLimitOffset(StringBuffer sql, int limit, int offset)
      Description copied from class: SQLDialect
      Alters the query provided so that limit and offset are natively dealt with. This might mean simply appending some extra directive to the query, or wrapping it into a bigger one.
      Overrides:
      applyLimitOffset in class SQLDialect
    • supportsSchemaForIndex

      protected boolean supportsSchemaForIndex()
      Description copied from class: SQLDialect
      Return true if the database supports individual schemas for indices.

      The SQL encoding would be CREATE INDEX SCHEMANAME.INDEXNAME ON ....

      The default is false and the encoding is CREATE INDEX INDEXNAME ON ....

      Overrides:
      supportsSchemaForIndex in class SQLDialect
      Returns:
      true or false
    • registerSqlTypeToSqlTypeNameOverrides

      public void registerSqlTypeToSqlTypeNameOverrides(Map<Integer,String> overrides)
      Description copied from class: SQLDialect
      Registers any overrides that should occur when mapping an integer sql type value to an underlying sql type name.

      The default implementation of this method does nothing. Subclasses should override in cases where:

      • database type metadata does not provide enough information to properly map
      • to support custom types (those not in Types)
      Overrides:
      registerSqlTypeToSqlTypeNameOverrides in class SQLDialect
    • canGroupOnGeometry

      public boolean canGroupOnGeometry()
      Description copied from class: SQLDialect
      Returns true if this database can "group by" on a Geometry column. Defaults to false, specific implementations with this capability should override
      Overrides:
      canGroupOnGeometry in class SQLDialect