Class HanaDialect


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

  • Method Details

    • isEstimatedExtentsEnabled

      public boolean isEstimatedExtentsEnabled()
    • setEstimatedExtentsEnabled

      public void setEstimatedExtentsEnabled(boolean estimatedExtentsEnabled)
    • 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
    • getGeometryTypeName

      public String getGeometryTypeName(Integer type)
      Description copied from class: SQLDialect
      Returns the name of a geometric type based on its integer constant.

      The constant, type, is registered in SQLDialect.registerSqlTypeNameToClassMappings(Map).

      This default implementation returns null, subclasses should override.

      Overrides:
      getGeometryTypeName 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
    • getOptimizedBounds

      public List<ReferencedEnvelope> getOptimizedBounds(String schema, SimpleFeatureType featureType, Connection cx) throws SQLException, IOException
      Description copied from class: SQLDialect
      Returns the bounds of all geometry columns in the layer using any approach that proves to be faster than the plain bounds aggregation (e.g., better than the "plain select extent(geom) from table" on PostGIS), or null if none exists or the fast method has not been enabled (e.g., if the fast method is just an estimate of the bounds you probably want the user to enable it manually)
      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
    • 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
    • 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
    • encodeGeometryColumnSimplified

      public void encodeGeometryColumnSimplified(GeometryDescriptor gatt, String prefix, int srid, StringBuffer sql, Double distance)
      Overrides:
      encodeGeometryColumnSimplified 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
    • decodeGeometryValue

      public Geometry decodeGeometryValue(GeometryDescriptor descriptor, ResultSet rs, int 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 specifying the column as an index.

      See #decodeGeometryValue(GeometryDescriptor, ResultSet, String, GeometryFactory) for a more in depth description.

      Overrides:
      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
    • lookupGeneratedValuesPostInsert

      public boolean lookupGeneratedValuesPostInsert()
      Description copied from class: SQLDialect
      Controls whether keys are looked up post or pre insert.

      When a row is inserted into a table, and a key is automatically generated it can be looked up before the insert occurs, or after the insert has been made. Returning false will cause the lookup to occur before the insert via SQLDialect.getNextAutoGeneratedValue(String, String, String, Connection). Returning true will cause the lookup to occur after the insert via SQLDialect.getLastAutoGeneratedValue(String, String, String, Connection).

      Subclasses returning false should implement:

      Subclasses returning true should implement:

      Overrides:
      lookupGeneratedValuesPostInsert 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
    • 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
    • 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
    • addSupportedHints

      protected void addSupportedHints(Set<Hints.Key> hints)
      Description copied from class: SQLDialect
      Add hints to the JDBC Feature Source. A subclass can override

      possible hints (but not limited to)

      Hints.GEOMETRY_GENERALIZATION Hints.GEOMETRY_SIMPLIFICATION

      Overrides:
      addSupportedHints 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
    • handleSelectHints

      public void handleSelectHints(StringBuffer sql, SimpleFeatureType featureType, Query query)
      Description copied from class: SQLDialect
      Used to apply search hints on the fully generated SQL (complete of select, from, where, sort, limit/offset)
      Overrides:
      handleSelectHints in class SQLDialect
    • 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.
    • getDesiredTablesType

      public String[] getDesiredTablesType()
      Overrides:
      getDesiredTablesType in class SQLDialect
      Returns:
      Table types filtered from jdbc DatabaseMetaData
    • 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.
    • setGeometryValue

      public void setGeometryValue(Geometry g, int dimension, int srid, Class binding, PreparedStatement ps, int column) throws SQLException
      Description copied from class: PreparedStatementSQLDialect
      Sets the geometry value into the prepared statement.
      Specified by:
      setGeometryValue in class PreparedStatementSQLDialect
      Parameters:
      g - The geometry
      srid - the geometry native srid (should be forced into the encoded geometry)
      binding - the geometry type
      ps - the prepared statement
      column - the column index where the geometry is to be set
      Throws:
      SQLException
    • 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
    • createPreparedFilterToSQL

      public PreparedFilterToSQL createPreparedFilterToSQL()
      Overrides:
      createPreparedFilterToSQL in class PreparedStatementSQLDialect