com.ing.data.cassandra.jdbc.metadata

Class ColumnMetadataResultSetBuilder

java.lang.Object

com.ing.data.cassandra.jdbc.metadata.AbstractMetadataResultSetBuilder

com.ing.data.cassandra.jdbc.metadata.ColumnMetadataResultSetBuilder

public class ColumnMetadataResultSetBuilder
extends AbstractMetadataResultSetBuilder

Utility class building metadata result sets (CassandraMetadataResultSet objects) related to columns.

Constructor Summary

Constructors

Constructor and Description
ColumnMetadataResultSetBuilder(CassandraStatement statement) Constructor.

Method Summary

Modifier and Type	Method and Description
CassandraMetadataResultSet	buildColumns(String schemaPattern, String tableNamePattern, String columnNamePattern) Builds a valid result set of the description of the table columns available in the given catalog (Cassandra cluster).

Methods inherited from class com.ing.data.cassandra.jdbc.metadata.AbstractMetadataResultSetBuilder

matchesPattern

Methods inherited from class java.lang.Object

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

Constructor Detail

ColumnMetadataResultSetBuilder

public ColumnMetadataResultSetBuilder(CassandraStatement statement)
                               throws SQLException

Constructor.

Parameters:

statement - The statement.

Throws:

SQLException - if a database access error occurs or this statement is closed.

Method Detail

buildColumns

public CassandraMetadataResultSet buildColumns(String schemaPattern,
                                               String tableNamePattern,
                                               String columnNamePattern)
                                        throws SQLException

Builds a valid result set of the description of the table columns available in the given catalog (Cassandra cluster). This method is used to implement the method DatabaseMetaData.getColumns(String, String, String, String).

Only table descriptions matching the catalog, schema, table and column name criteria are returned. They are ordered by TABLE_CAT, TABLE_SCHEM, TABLE_NAME and ORDINAL_POSITION.

The columns of this result set are:

1. TABLE_CAT String => table catalog, may be null: here is the Cassandra cluster name (if available).
2. TABLE_SCHEM String => table schema, may be null: here is the keyspace the table is member of.
3. TABLE_NAME String => table name.
4. COLUMN_NAME String => column name.
5. DATA_TYPE int => SQL type from Types.
6. TYPE_NAME String => Data source dependent type name, for a UDT the type name is fully qualified.
7. COLUMN_SIZE int => column size.
8. BUFFER_LENGTH int => not used: always 0 here.
9. DECIMAL_DIGITS int => the number of fractional digits, null is returned for data types where it is not applicable. Always null here.
10. NUM_PREC_RADIX int => Radix (typically either 10 or 2).
11. NULLABLE int => is NULL allowed:
    • DatabaseMetaData.columnNoNulls - might not allow NULL values
    • DatabaseMetaData.columnNullable - definitely allows NULL values
    • DatabaseMetaData.columnNullableUnknown - nullability unknown
    Always DatabaseMetaData.columnNoNulls here.
12. REMARKS String => comment describing column, may be null: always null here since comments on columns does not exist in Cassandra.
13. COLUMN_DEF String => default value for the column, which should be interpreted as a string when the value is enclosed in single quotes, may be null. Always null here.
14. SQL_DATA_TYPE int => is not used: always null here.
15. SQL_DATETIME_SUB int => is not used: always null here.
16. CHAR_OCTET_LENGTH int => for char types the maximum number of bytes in the column.
17. ORDINAL_POSITION int => index of column in table (starting at 1).
18. IS_NULLABLE String => ISO rules are used to determine the nullability for a column:
    • YES - if the column can include NULLs
    • NO - if the column cannot include NULLs
    • empty string - if the nullability for the column is unknown
    Always empty here.
19. SCOPE_CATALOG String => catalog of table that is the scope of a reference attribute (null if DATA_TYPE isn't REF). Always null here.
20. SCOPE_SCHEMA String => schema of table that is the scope of a reference attribute (null if DATA_TYPE isn't REF). Always null here.
21. SCOPE_TABLE String => table name that is the scope of a reference attribute (null if DATA_TYPE isn't REF). Always null here.
22. SOURCE_DATA_TYPE short => source type of a distinct type or user-generated Ref type, SQL type from Types (null if DATA_TYPE isn't DISTINCT or user-generated REF). Always null here.
23. IS_AUTOINCREMENT String => Indicates whether this column is auto-incremented:
    • YES - if the column is auto-incremented
    • NO - if the column is not auto-incremented
    • empty string - if it cannot be determined whether the column is auto incremented parameter is unknown
    Always NO here.
24. IS_GENERATEDCOLUMN String => Indicates whether this is a generated column:
    • YES - if this is a generated column
    • NO - if this is not a generated column
    • empty string - if it cannot be determined whether this is a generated column
    Always NO here.

Parameters:

schemaPattern - A schema name pattern. It must match the schema name as it is stored in the database; "" retrieves those without a schema and null means that the schema name should not be used to narrow the search. Using "" as the same effect as null because here the schema corresponds to the keyspace and Cassandra tables cannot be defined outside a keyspace.

tableNamePattern - A table name pattern. It must match the table name as it is stored in the database.

columnNamePattern - A column name pattern. It must match the column name as it is stored in the database.

Returns:

A valid result set for implementation of DatabaseMetaData.getColumns(String, String, String, String).

Throws:

SQLException - when something went wrong during the creation of the result set.