Package com.exasol.adapter.jdbc

Class BaseColumnMetadataReader

java.lang.Object

com.exasol.adapter.jdbc.AbstractMetadataReader

com.exasol.adapter.jdbc.BaseColumnMetadataReader

All Implemented Interfaces:

ColumnMetadataReader, MetadataReader

public class BaseColumnMetadataReader
extends AbstractMetadataReader
implements ColumnMetadataReader

This class implements a mapper that reads column metadata from the remote database and converts it into JDBC information.

Field Summary

Fields

Modifier and Type	Field	Description
static String	AUTOINCREMENT_COLUMN	Key for autoincrement
static String	CHAR_OCTET_LENGTH_COLUMN	Key for char octet length
static String	DATA_TYPE_COLUMN	Key for data type
static String	DEFAULT_VALUE_COLUMN	Key for the default value
static String	NAME_COLUMN	Key for column name
static String	NULLABLE_COLUMN	Key for is nullable
static String	REMARKS_COLUMN	Key for the comment
static String	SCALE_COLUMN	Key for decimal digits
static String	SIZE_COLUMN	Key for column size
static String	TYPE_NAME_COLUMN	Key for type name

Fields inherited from class com.exasol.adapter.jdbc.AbstractMetadataReader

connection, exaMetadata, properties

Constructor Summary

Constructors

Constructor	Description
BaseColumnMetadataReader(Connection connection, com.exasol.adapter.AdapterProperties properties, com.exasol.ExaMetadata exaMetadata, IdentifierConverter identifierConverter)	Create a new instance of a ColumnMetadataReader.

Method Summary

Modifier and Type	Method	Description
protected com.exasol.adapter.metadata.DataType	convertDecimal(int jdbcPrecision, int scale)	Build a data type for a decimal value.
protected ResultSet	getColumnMetadata(String catalogName, String schemaName, String tableName)	Read column metadata from JDBC driver escaping potential SQL wild cards in the names of schema and table.
protected ResultSet	getColumnMetadataAllowingPatterns(String catalogName, String schemaNamePattern, String tableNamePattern)	Read column metadata from JDBC driver without escaping potential SQL wild cards in the names of schema and table.
protected List<com.exasol.adapter.metadata.ColumnMetadata>	getColumnsFromResultSet(ResultSet remoteColumns)	Read the columns result set.
protected com.exasol.adapter.metadata.DataType	getNumberTypeFromProperty(String property)	Parse a number type property.
protected boolean	isRemoteColumnNullable(ResultSet remoteColumn, String columnName)	Check if a column a nullable.
protected String	mapColumnName(String columnName)	Convert the column name.
List<com.exasol.adapter.metadata.ColumnMetadata>	mapColumns(String tableName)	Map a metadata for a list of columns to Exasol metadata.
protected List<com.exasol.adapter.metadata.ColumnMetadata>	mapColumns(String catalogName, String schemaName, String tableName)	Read the columns metadata from a result set.
com.exasol.adapter.metadata.DataType	mapJdbcType(JDBCTypeDescription jdbcTypeDescription)	Map type information from JDBC to the Exasol type information.
protected com.exasol.adapter.metadata.DataType	mapJdbcTypeNumericToDecimalWithFallbackToDouble(JDBCTypeDescription jdbcTypeDescription)	Map a NUMERIC column to an Exasol DECIMAL
void	mapOrSkipColumn(ResultSet remoteColumns, List<com.exasol.adapter.metadata.ColumnMetadata> columns)	Read the column metadata from result set if supported.
protected String	readColumnName(ResultSet columns)	Read the column name form result set.
JDBCTypeDescription	readJdbcTypeDescription(ResultSet remoteColumn)	Read the JDBC type description of a column.
protected boolean	supportsTimestampsWithNanoPrecision()	Whether the Exasol database supports timestamp with precision up to nanoseconds.

Methods inherited from class com.exasol.adapter.jdbc.AbstractMetadataReader

getCatalogNameFilter, getSchemaNameFilter

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

NAME_COLUMN

public static final String NAME_COLUMN

Key for column name

See Also:

Constant Field Values

DATA_TYPE_COLUMN

public static final String DATA_TYPE_COLUMN

Key for data type

See Also:

Constant Field Values

SIZE_COLUMN

public static final String SIZE_COLUMN

Key for column size

See Also:

Constant Field Values

SCALE_COLUMN

public static final String SCALE_COLUMN

Key for decimal digits

See Also:

Constant Field Values

CHAR_OCTET_LENGTH_COLUMN

public static final String CHAR_OCTET_LENGTH_COLUMN

Key for char octet length

See Also:

Constant Field Values

TYPE_NAME_COLUMN

public static final String TYPE_NAME_COLUMN

Key for type name

See Also:

Constant Field Values

REMARKS_COLUMN

public static final String REMARKS_COLUMN

Key for the comment

See Also:

Constant Field Values

DEFAULT_VALUE_COLUMN

public static final String DEFAULT_VALUE_COLUMN

Key for the default value

See Also:

Constant Field Values

AUTOINCREMENT_COLUMN

public static final String AUTOINCREMENT_COLUMN

Key for autoincrement

See Also:

Constant Field Values

NULLABLE_COLUMN

public static final String NULLABLE_COLUMN

Key for is nullable

See Also:

Constant Field Values

Constructor Detail

BaseColumnMetadataReader

public BaseColumnMetadataReader(Connection connection,
                                com.exasol.adapter.AdapterProperties properties,
                                com.exasol.ExaMetadata exaMetadata,
                                IdentifierConverter identifierConverter)

Create a new instance of a ColumnMetadataReader.

Parameters:

connection - JDBC connection through which the column metadata is read from the remote database

properties - user-defined adapter properties

exaMetadata - metadata of the Exasol database

identifierConverter - converter between source and Exasol identifiers

Method Detail

supportsTimestampsWithNanoPrecision

protected boolean supportsTimestampsWithNanoPrecision()

Whether the Exasol database supports timestamp with precision up to nanoseconds.

Returns:

true if Exasol database supports timestamps with nanoseconds precision false otherwise.

mapColumns

public List<com.exasol.adapter.metadata.ColumnMetadata> mapColumns(String tableName)

Map a metadata for a list of columns to Exasol metadata.

Specified by:

mapColumns in interface ColumnMetadataReader

Parameters:

tableName - the table for which the columns are mapped

Returns:

list of Exasol column metadata objects

mapColumns

protected List<com.exasol.adapter.metadata.ColumnMetadata> mapColumns(String catalogName,
                                                                      String schemaName,
                                                                      String tableName)

Read the columns metadata from a result set.

Parameters:

catalogName - catalog name

schemaName - schema name

tableName - table name

Returns:

list with column metadata

getColumnMetadata

protected ResultSet getColumnMetadata(String catalogName,
                                      String schemaName,
                                      String tableName)
                               throws SQLException

Read column metadata from JDBC driver escaping potential SQL wild cards in the names of schema and table.

Parameters:

catalogName - catalog name

schemaName - schema name, potential SQL wildcards will be escaped

tableName - table name, potential SQL wildcards will be escaped

Returns:

list with metadata for all columns of the respective catalog, schema, and table

Throws:

SQLException - in case of failures

getColumnMetadataAllowingPatterns

protected ResultSet getColumnMetadataAllowingPatterns(String catalogName,
                                                      String schemaNamePattern,
                                                      String tableNamePattern)
                                               throws SQLException

Read column metadata from JDBC driver without escaping potential SQL wild cards in the names of schema and table.

Parameters:

catalogName - catalog name

schemaNamePattern - schema name pattern, may contain SQL wildcards

tableNamePattern - table name pattern, may contain SQL wildcards

Returns:

list with metadata for all columns of the respective catalog, matching schema name pattern, and table name pattern

Throws:

SQLException - in case of failures

getColumnsFromResultSet

protected List<com.exasol.adapter.metadata.ColumnMetadata> getColumnsFromResultSet(ResultSet remoteColumns)
                                                                            throws SQLException

Read the columns result set.

Parameters:

remoteColumns - column result set.

Returns:

list of column metadata

Throws:

SQLException - if read fails

mapOrSkipColumn

public void mapOrSkipColumn(ResultSet remoteColumns,
                            List<com.exasol.adapter.metadata.ColumnMetadata> columns)
                     throws SQLException

Read the column metadata from result set if supported. Otherwise, skip.

Parameters:

remoteColumns - column result set

columns - list to append column to

Throws:

SQLException - if read fails

readJdbcTypeDescription

public JDBCTypeDescription readJdbcTypeDescription(ResultSet remoteColumn)
                                            throws SQLException

Read the JDBC type description of a column.

Parameters:

remoteColumn - result set column

Returns:

JDBC type description

Throws:

SQLException - if read fails

isRemoteColumnNullable

protected boolean isRemoteColumnNullable(ResultSet remoteColumn,
                                         String columnName)

Check if a column a nullable.

Parameters:

remoteColumn - column result set

columnName - column name

Returns:

true if remote column is nullable

readColumnName

protected String readColumnName(ResultSet columns)
                         throws SQLException

Read the column name form result set.

Parameters:

columns - column result set

Returns:

column name

Throws:

SQLException - if read fails

mapJdbcType

public com.exasol.adapter.metadata.DataType mapJdbcType(JDBCTypeDescription jdbcTypeDescription)

Description copied from interface: ColumnMetadataReader

Map type information from JDBC to the Exasol type information.

Override this method in a dedicated mapper if you need dialect specific behavior.

Specified by:

mapJdbcType in interface ColumnMetadataReader

Parameters:

jdbcTypeDescription - parameter object describing the type from the JDBC perspective

Returns:

Exasol data type information

convertDecimal

protected com.exasol.adapter.metadata.DataType convertDecimal(int jdbcPrecision,
                                                              int scale)

Build a data type for a decimal value.

Parameters:

jdbcPrecision - precision

scale - scale

Returns:

built data type

mapColumnName

protected String mapColumnName(String columnName)

Convert the column name.

Parameters:

columnName - column name

Returns:

column name

mapJdbcTypeNumericToDecimalWithFallbackToDouble

protected com.exasol.adapter.metadata.DataType mapJdbcTypeNumericToDecimalWithFallbackToDouble(JDBCTypeDescription jdbcTypeDescription)

Map a NUMERIC column to an Exasol DECIMAL

If the precision of the remote column exceeds the maximum precision of an Exasol DECIMAL, the column is mapped to an Exasol DOUBLE instead.

Parameters:

jdbcTypeDescription - parameter object describing the type from the JDBC perspective

Returns:

Exasol DECIMAL if precision is less than or equal maximum precision, DOUBLE otherwise.

getNumberTypeFromProperty

protected com.exasol.adapter.metadata.DataType getNumberTypeFromProperty(String property)

Parse a number type property.

Parameters:

property - formatted string: <precision>,<scale>

Returns:

data type