Class DB2SQLDialect
- Object
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- SQLDialect
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- DB2SQLDialect
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public class DB2SQLDialect extends SQLDialect
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Field Summary
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Fields inherited from class SQLDialect
BASE_DBMS_CAPABILITIES, dataStore, forceLongitudeFirst, LOGGER, UNWRAPPER_NOT_FOUND, uwMap
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Constructor Summary
Constructors Constructor Description DB2SQLDialect(JDBCDataStore dataStore, DB2DialectInfo info)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method 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.boolean
canGroupOnGeometry()
Returns true if this database can "group by" on a Geometry column.CoordinateReferenceSystem
createCRS(int srid, Connection cx)
Turns the specified srid into aCoordinateReferenceSystem
, or returnsnull
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. *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()
Returntrue
if the database supports individual schemas for indices.-
Methods inherited from class SQLDialect
applyHintsOnVirtualTables, canSimplifyPoints, convertValue, createIndex, dropIndex, encodeColumnAlias, encodeColumnName, encodeColumnType, encodeCreateTable, encodeGeometryColumnSimplified, encodeJoin, encodePostColumnCreateTable, encodePostCreateTable, encodePostSelect, encodeSchemaName, encodeTableAlias, encodeTableName, escapeName, getAggregateConverter, getDefaultVarcharSize, getDesiredTablesType, getGeometryDimension, getIndexes, getLastAutoGeneratedValue, getLastAutoGeneratedValue, getMapping, getMapping, getNameEscape, getNextAutoGeneratedValue, getPkColumnValue, getPrimaryKey, getRestrictions, getResultTypes, getSQLType, handleSelectHints, handleUserDefinedType, initializeConnection, isAggregatedSortSupported, isArray, isAutoCommitQuery, isGroupBySupported, ne, postCreateAttribute, postCreateFeatureType, postDropTable, preDropTable, registerAggregateFunctions, registerSqlTypeToSqlTypeNameOverrides, splitFilter, unwrapConnection
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Constructor Detail
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DB2SQLDialect
public DB2SQLDialect(JDBCDataStore dataStore, DB2DialectInfo info)
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Method Detail
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getDb2DialectInfo
public DB2DialectInfo getDb2DialectInfo()
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createCRS
public CoordinateReferenceSystem createCRS(int srid, Connection cx) throws SQLException
Description copied from class:SQLDialect
Turns the specified srid into aCoordinateReferenceSystem
, or returnsnull
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 classSQLDialect
- Throws:
SQLException
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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 classSQLDialect
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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 classSQLDialect
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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 classSQLDialect
- Parameters:
schemaName
- The database schema, could benull
.tableName
- The table, nevernull
.columnName
- The column name, nevernull
cx
- The database connection.- Throws:
SQLException
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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
, orasWKB
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 classSQLDialect
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encodeGeometryColumn
public void encodeGeometryColumn(GeometryDescriptor gatt, String prefix, StringBuffer sql)
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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 classSQLDialect
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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 viaSQLDialect.getLastAutoGeneratedValue(String, String, String, Connection)
.DB2 implements:
- Overrides:
lookupGeneratedValuesPostInsert
in classSQLDialect
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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 classSQLDialect
- Parameters:
schema
- The database schema, if any, or nullfeatureType
- 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
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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 classSQLDialect
- Parameters:
rs
- A result setcolumn
- Index into the result set which points at the spatial extent value.cx
- The database connection.- Throws:
SQLException
IOException
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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 );
null
values.The factory parameter should be used to instantiate any geometry objects.
- Specified by:
decodeGeometryValue
in classSQLDialect
- Throws:
IOException
SQLException
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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 classSQLDialect
- Throws:
IOException
SQLException
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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 classSQLDialect
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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 classSQLDialect
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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 classSQLDialect
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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 classSQLDialect
- Parameters:
schemaName
- The name of the schema, may benull
.featureType
- The feature type that has just been created on the database.cx
- Database connection.- Throws:
SQLException
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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 classSQLDialect
- Parameters:
schemaName
- The schema name, this might benull
.tableName
- The table name.columnName
- The column name.cx
- The database connection.- Throws:
SQLException
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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 classSQLDialect
- Parameters:
schemaName
- The schema name, this might benull
.sequenceName
- The name of the sequence.cx
- The database connection.- Returns:
- The next value of the sequence, or
null
. - Throws:
SQLException
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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 classSQLDialect
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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 returnsfalse
. Subclasses should override this method, this default implementation returnstrue
.
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 classSQLDialect
- Parameters:
schemaName
- The schema of the table, might benull
..tableName
- The name of the table.cx
- Database connection.- Throws:
SQLException
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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 classSQLDialect
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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 classSQLDialect
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encodeGeometryColumnGeneralized
public void encodeGeometryColumnGeneralized(GeometryDescriptor gatt, String prefix, int srid, StringBuffer sql, Double distance)
- Overrides:
encodeGeometryColumnGeneralized
in classSQLDialect
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addSupportedHints
protected void addSupportedHints(Set<Hints.Key> hints)
Description copied from class:SQLDialect
Add hints to the JDBC Feature Source. A subclass can overridepossible hints (but not limited to)
- Overrides:
addSupportedHints
in classSQLDialect
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isFunctionEncodingEnabled
public boolean isFunctionEncodingEnabled()
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setFunctionEncodingEnabled
public void setFunctionEncodingEnabled(boolean functionEncodingEnabled)
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isLooseBBOXEnabled
public boolean isLooseBBOXEnabled()
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setLooseBBOXEnabled
public void setLooseBBOXEnabled(boolean looseBBOXEnabled)
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isUseSelectivity
public boolean isUseSelectivity()
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setUseSelectivity
public void setUseSelectivity(boolean useSelectivity)
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supportsSchemaForIndex
protected boolean supportsSchemaForIndex()
Description copied from class:SQLDialect
Returntrue
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 classSQLDialect
- Returns:
- true or false
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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 classSQLDialect
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