Class HanaDialect


  • public class HanaDialect
    extends PreparedStatementSQLDialect
    A prepared statement SQL dialect for SAP HANA.
    Author:
    Stefan Uhrig, SAP SE
    • Constructor Detail

    • Method Detail

      • setFunctionEncodingEnabled

        public void setFunctionEncodingEnabled​(boolean enabled)
      • setSimplifyDisabled

        public void setSimplifyDisabled​(boolean disabled)
      • setSelectHints

        public void setSelectHints​(String selectHints)
      • 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
      • registerSqlTypeNameToClassMappings

        public void registerSqlTypeNameToClassMappings​(Map<String,​Class<?>> mappings)
        Description copied from class: SQLDialect
        Registers the sql type name 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:
        registerSqlTypeNameToClassMappings in class SQLDialect
      • 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
      • 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
      • 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
      • getGeometryDimension

        public int getGeometryDimension​(String schemaName,
                                        String tableName,
                                        String columnName,
                                        Connection cx)
                                 throws SQLException
        Description copied from class: SQLDialect
        Returns the dimension of the coordinates in the geometry. Defaults to 2, subclasses can override it.

        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 dimension cannot be determined, this method should return 2

        Overrides:
        getGeometryDimension 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
      • createCRS

        public CoordinateReferenceSystem createCRS​(int srid,
                                                   Connection cx)
                                            throws SQLException
        Description copied from class: SQLDialect
        Turns the specified srid into a CoordinateReferenceSystem, or returns null if not possible.

        Note this implementation takes account of SQLDialect.forceLongitudeFirst which should be set when longitude first (XY) axis ordering is required.

        The implementation might just use CRS.decode("EPSG:" + srid), but most spatial databases will have their own SRS database that can be queried as well.

        As a rule of thumb you should override this method if your spatial database uses codes that are not part of the EPSG standard database, of if for some reason you deem it preferable to use your database definition instead of an official EPSG one.

        Most overrides will try out to decode the official EPSG code first, and fall back on the custom database definition otherwise

        Overrides:
        createCRS in class SQLDialect
        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
      • encodeGeometryColumn

        public void encodeGeometryColumn​(GeometryDescriptor gatt,
                                         String prefix,
                                         int srid,
                                         Hints hints,
                                         StringBuffer sql)
        Description copied from class: SQLDialect
        Encodes the name of a geometry column in a SELECT statement.

        This method should wrap the column name in any functions that are used to retrieve its value. For instance, often it is necessary to use the function asText, or asWKB when fetching a geometry.

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

        Example:

           
           sql.append( "asText(" );
           column( gatt.getLocalName(), sql );
           sql.append( ")" );
           
         
        Overrides:
        encodeGeometryColumn in class SQLDialect
      • 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
      • encodeCreateTable

        public void encodeCreateTable​(StringBuffer sql)
        Description copied from class: SQLDialect
        Encodes the CREATE TABLE statement.

        Default implementation adds "CREATE TABLE" to the sql buffer. Subclasses may choose to override to handle db specific syntax.

        Overrides:
        encodeCreateTable in class SQLDialect
      • 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.
      • postCreateTable

        public void postCreateTable​(String schemaName,
                                    SimpleFeatureType featureType,
                                    Connection cx)
                             throws SQLException,
                                    IOException
        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
        IOException
      • 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
      • postDropTable

        public void postDropTable​(String schemaName,
                                  SimpleFeatureType featureType,
                                  Connection cx)
                           throws SQLException
        Description copied from class: SQLDialect
        Callback which executes after a table has been dropped.

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

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

        public int getDefaultVarcharSize()
        Description copied from class: SQLDialect
        Determines the default length that a varchar field should be when creating datastore tables from feature types.

        Some dialects allow no length to be specified for varchar fields (PostGIS for example) however others require a maximum length to be set.

        Subclasses can override this method and either return -1 to specify that no length is required, or otherwise return an appropriate default length for varchars of that dialect.

        Overrides:
        getDefaultVarcharSize 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
      • applyHintsOnVirtualTables

        public boolean applyHintsOnVirtualTables()
        Description copied from class: SQLDialect
        Controls whether select hints should be added to queries on virtual tables.
        Overrides:
        applyHintsOnVirtualTables in class SQLDialect
        Returns:
        True if select hints hould be added to queries on virtual tables, false otherwise.
      • prepareGeometryValue

        public void prepareGeometryValue​(Class<? extends Geometry> gClass,
                                         int dimension,
                                         int srid,
                                         Class binding,
                                         StringBuffer sql)
        Description copied from class: PreparedStatementSQLDialect
        Prepares the geometry value for a prepared statement.

        This method should be overridden if the implementation needs to wrap the geometry placeholder in the function. The default implementationg just appends the default placeholder: '?'.

        Overrides:
        prepareGeometryValue in class PreparedStatementSQLDialect
        Parameters:
        gClass - The geometry class.
        dimension - The dimensions (2,3,4) of the coordinates, or -1 if unknown
        srid - The spatial reference system of the geometry, or -1 if unknown
        binding - The class of the geometry.
        sql - The prepared sql statement buffer.
      • setValue

        public void setValue​(Object value,
                             Class<?> binding,
                             AttributeDescriptor att,
                             PreparedStatement ps,
                             int column,
                             Connection cx)
                      throws SQLException
        Description copied from class: PreparedStatementSQLDialect
        Sets a value in a prepared statement, for "basic types" (non-geometry).

        Subclasses should override this method if they need to do something custom or they wish to support non-standard types.

        Overrides:
        setValue in class PreparedStatementSQLDialect
        Parameters:
        value - the value.
        binding - The class of the value.
        att - Optionally the descriptor of the respective attribute to provide native type information.
        ps - The prepared statement.
        column - The column the value maps to.
        cx - The database connection.
        Throws:
        SQLException