DB2SQLDialect (Geotools modules 21.0 API)

Object
- SQLDialect
- - DB2SQLDialect

public class DB2SQLDialect
extends SQLDialect

Field Summary
- Fields inherited from class SQLDialect
  BASE_DBMS_CAPABILITIES, dataStore, LOGGER

Constructor Summary

Constructors
Constructor and Description

DB2SQLDialect(JDBCDataStore dataStore, DB2DialectInfo info)

Constructors
Constructor and Description
`DB2SQLDialect(JDBCDataStore dataStore, DB2DialectInfo info)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`protected void`	`addSupportedHints(Set<Hints.Key> hints)` Add hints to the JDBC Feature Source.
`void`	`applyLimitOffset(StringBuffer sql, int limit, int offset)` Alters the query provided so that limit and offset are natively dealt with.
`CoordinateReferenceSystem`	`createCRS(int srid, Connection cx)` Turns the specified srid into a `CoordinateReferenceSystem`, or returns `null` if not possible.
`Envelope`	`decodeGeometryEnvelope(ResultSet rs, int column, Connection cx)` Decodes the result of a spatial extent function in a SELECT statement.
`Geometry`	`decodeGeometryValue(GeometryDescriptor descriptor, ResultSet rs, int column, GeometryFactory factory, Connection cx, Hints hints)` Decodes a geometry value from the result of a query specifying the column as an index.
`Geometry`	`decodeGeometryValue(GeometryDescriptor descriptor, ResultSet rs, String name, GeometryFactory factory, Connection cx, Hints hints)` Decodes a geometry value from the result of a query.
`void`	`encodeGeometryColumn(GeometryDescriptor gatt, String prefix, int srid, Hints hints, StringBuffer sql)` Encodes the name of a geometry column in a SELECT statement.
`void`	`encodeGeometryColumn(GeometryDescriptor gatt, String prefix, StringBuffer sql)`
`void`	`encodeGeometryColumnGeneralized(GeometryDescriptor gatt, String prefix, int srid, StringBuffer sql, Double distance)`
`void`	`encodeGeometryEnvelope(String tableName, String geometryColumn, StringBuffer sql)` Encodes the spatial extent function of a geometry column in a SELECT statement.
`String`	`encodeNextSequenceValue(String schemaName, String sequenceName)` Encodes how to get the next sequence value from the DB.
`void`	`encodePrimaryKey(String column, StringBuffer sql)` Encodes the primary key definition in a CREATE TABLE statement.
`DB2DialectInfo`	`getDb2DialectInfo()`
`Integer`	`getGeometrySRID(String schemaName, String tableName, String columnName, Connection cx)` Returns the spatial reference system identifier (srid) for a particular geometry column.
`String`	`getGeometryTypeName(Integer type)` Returns the name of a geometric type based on its integer constant.
`Object`	`getNextSequenceValue(String schemaName, String sequenceName, Connection cx)` Obtains the next value of a sequence, incrementing the sequence to the next state in the process.
`List<ReferencedEnvelope>`	`getOptimizedBounds(String schema, SimpleFeatureType featureType, Connection cx)` Since DB2 V10.
`String`	`getSequenceForColumn(String schemaName, String tableName, String columnName, Connection cx)` Determines the name of the sequence (if any) which is used to increment generate values for a table column.
`boolean`	`includeTable(String schemaName, String tableName, Connection cx)` Determines if the specified table should be included in those published by the datastore.
`boolean`	`isFunctionEncodingEnabled()`
`boolean`	`isLimitOffsetSupported()` Returns true if this dialect can encode both Query.getStartIndex() and Query.getMaxFeatures() into native SQL.
`boolean`	`isLooseBBOXEnabled()`
`boolean`	`isUseSelectivity()`
`boolean`	`lookupGeneratedValuesPostInsert()` Controls whether keys are looked up post or pre insert.
`void`	`postCreateTable(String schemaName, SimpleFeatureType featureType, Connection cx)` Callback to execute any additional sql statements post a create table statement.
`void`	`registerClassToSqlMappings(Map<Class<?>,Integer> mappings)` 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.
`void`	`registerSqlTypeNameToClassMappings(Map<String,Class<?>> mappings)` Registers the sql type name to java type mappings that the dialect uses when reading and writing objects to and from the database.
`void`	`registerSqlTypeToClassMappings(Map<Integer,Class<?>> mappings)` Registers the sql type to java type mappings that the dialect uses when reading and writing objects to and from the database.
`void`	`setFunctionEncodingEnabled(boolean functionEncodingEnabled)`
`void`	`setLooseBBOXEnabled(boolean looseBBOXEnabled)`
`void`	`setUseSelectivity(boolean useSelectivity)`
`protected boolean`	`supportsSchemaForIndex()` Return `true` if the database supports individual schemas for indices.

Methods inherited from class SQLDialect
createIndex, dropIndex, encodeAggregateFunction, encodeAggregateFunctionPostfix, encodeAggregateFunctionPrefix, encodeColumnAlias, encodeColumnName, encodeColumnName, encodeColumnType, encodeCreateTable, encodeGeometryColumn, encodeGeometryColumn, encodeGeometryColumnGeneralized, encodeGeometryColumnSimplified, encodeGeometryColumnSimplified, encodeJoin, encodePostColumnCreateTable, encodePostCreateTable, encodePostSelect, encodeSchemaName, encodeTableAlias, encodeTableName, getDefaultVarcharSize, getDesiredTablesType, getGeometryDimension, getIndexes, getLastAutoGeneratedValue, getLastAutoGeneratedValue, getMapping, getNameEscape, getNextAutoGeneratedValue, getPkColumnValue, getPrimaryKey, handleSelectHints, handleUserDefinedType, initializeConnection, isAggregatedSortSupported, isAutoCommitQuery, isGroupBySupported, ne, postCreateAttribute, postCreateFeatureType, postDropTable, preDropTable, registerAggregateFunctions, registerFunctions, registerSqlTypeToSqlTypeNameOverrides, splitFilter

Methods inherited from class Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - DB2SQLDialect
```
public DB2SQLDialect(JDBCDataStore dataStore,
                     DB2DialectInfo info)
```
- Method Detail
  - getDb2DialectInfo
```
public DB2DialectInfo getDb2DialectInfo()
```
  - 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.
    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
    
    Returns:
    
    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
  - 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
  - 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( ")" );
   
 
```
    This default implementation calls the deprecated SQLDialect.encodeGeometryColumn(GeometryDescriptor, String, int, StringBuffer) version of this method for backward compatibility reasons.
    Overrides:
    
    encodeGeometryColumn in class SQLDialect
  - encodeGeometryColumn
```
public void encodeGeometryColumn(GeometryDescriptor gatt,
                                 String prefix,
                                 StringBuffer sql)
```
  - 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 SQLDialect.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:
    - SQLDialect.getLastAutoGeneratedValue(String, String, String, Connection)
    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
  - 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.
    
    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
  - 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
    
    See Also:
    
    #decodeGeometryValue(GeometryDescriptor, ResultSet, String, GeometryFactory)}.
  - 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
  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 Returns: 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 encodeGeometryColumnGeneralized public void encodeGeometryColumnGeneralized(GeometryDescriptor gatt, String prefix, int srid, StringBuffer sql, Double distance) Overrides: encodeGeometryColumnGeneralized 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 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

Class DB2SQLDialect

Field Summary

Fields inherited from class SQLDialect

Constructor Summary

Method Summary

Methods inherited from class SQLDialect

Methods inherited from class Object

Constructor Detail

DB2SQLDialect

Method Detail

getDb2DialectInfo

createCRS

encodePrimaryKey

getGeometryTypeName

getGeometrySRID

encodeGeometryColumn

encodeGeometryColumn

encodeGeometryEnvelope

lookupGeneratedValuesPostInsert

getOptimizedBounds

decodeGeometryEnvelope

decodeGeometryValue

decodeGeometryValue

registerClassToSqlMappings

registerSqlTypeToClassMappings

registerSqlTypeNameToClassMappings

postCreateTable

getSequenceForColumn

getNextSequenceValue

encodeNextSequenceValue

includeTable

isLimitOffsetSupported

applyLimitOffset

encodeGeometryColumnGeneralized

addSupportedHints

isFunctionEncodingEnabled

setFunctionEncodingEnabled

isLooseBBOXEnabled

setLooseBBOXEnabled

isUseSelectivity

setUseSelectivity

supportsSchemaForIndex