Package org.geotools.data.db2

Class DB2SQLDialect

    • Method Detail

      • 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

      • 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

      • 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

      • 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

      • 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

      • lookupGeneratedValuesPostInsert

        public boolean lookupGeneratedValuesPostInsert()
        Controls whether keys are looked up post or pre insert.

        TODO TODO TODO Due to DB2 implementation problems, ps.addBatch(), ps.executeBatch() doesn't work for auto-generated identity key columns. This function should return 'true' to make the overall logic work with auto-generated columns but this breaks the logic for sequence generated key columns so for now, return 'false'.

        Part of the reason for the breakage is that if 'true', KeysFetcher will add to the INSERT statement NEXT VALUE FOR seq_name but doesn't include the schema so an error occurs since the test setup specifies the sequence schema name as 'geotools' which is different from the default which is the connection id. It isn't clear why the 'geotools' schema isn't being specified. Even if this was corrected, the current DB2 JDBC support wouldn't correctly get the inserted key values later.

        Another problem is that if 'true', JDBCDataStore::insertPS executes: ps = cx.prepareStatement(sql, keysFetcher.getColumnNames()); which causes a failure with ps.addBatch() because it defaults to uppercase for the key column while the table was defined with a lowercase key column - this is a DB2 JDBC defect which is not likely to be fixed.

        It isn't really clear why this method is being called for sequence key columns. Fixing this probably requires significant changes to the core JDBC logic which I'm not prepared to do. -- David Adler 04/18/2017

        When a row is inserted into a table, and a key is automatically generated DB2 allows the generated key to be retrieved after the insert. The DB2 dialect returns true to cause the lookup to occur after the insert via SQLDialect.getLastAutoGeneratedValue(String, String, String, Connection).

        DB2 implements:

        Overrides:
        lookupGeneratedValuesPostInsert in class SQLDialect

      • getOptimizedBounds

        public List<ReferencedEnvelope> getOptimizedBounds​(String schema,
                                                   SimpleFeatureType featureType,
                                                   Connection cx)
                                            throws SQLException,
                                                   IOException
        Since DB2 V10.

        Look in the system view "db2gse.st_geometry_columns" and check for min_x,min_y,max_x,max_y

        If ALL geometry attributes have precalculated extents, return the list of the envelopes. If only one of them has no precalculated extent, return null

        Overrides:
        getOptimizedBounds in class SQLDialect
        Parameters:
        schema - The database schema, if any, or null
        featureType - The feature type containing the geometry columns whose bounds need to computed. Mind, it may be retyped and thus contain less geometry columns than the table
        Returns:
        a list of referenced envelopes (some of which may be null or empty)
        Throws:
        SQLException
        IOException

      • decodeGeometryValue

        public Geometry decodeGeometryValue​(GeometryDescriptor descriptor,
                                    ResultSet rs,
                                    String name,
                                    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

      • 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

      • 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

      • 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

      • 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

      • 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

      • 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

      • 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

      • isFunctionEncodingEnabled

        public boolean isFunctionEncodingEnabled()

      • setFunctionEncodingEnabled

        public void setFunctionEncodingEnabled​(boolean functionEncodingEnabled)

      • isLooseBBOXEnabled

        public boolean isLooseBBOXEnabled()

      • setLooseBBOXEnabled

        public void setLooseBBOXEnabled​(boolean looseBBOXEnabled)

      • isUseSelectivity

        public boolean isUseSelectivity()

      • setUseSelectivity

        public void setUseSelectivity​(boolean useSelectivity)

      • 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

      • 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