com.ing.data.cassandra.jdbc.metadata

Class TableMetadataResultSetBuilder

java.lang.Object

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

com.ing.data.cassandra.jdbc.metadata.TableMetadataResultSetBuilder

public class TableMetadataResultSetBuilder
extends AbstractMetadataResultSetBuilder

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

Constructor Summary

Constructors

Constructor and Description
TableMetadataResultSetBuilder(CassandraStatement statement) Constructor.

Method Summary

Modifier and Type	Method and Description
CassandraMetadataResultSet	buildBestRowIdentifier(String schema, String table, int scope) Builds a valid result set of the description of a table's optimal set of columns that uniquely identifies a row.
CassandraMetadataResultSet	buildIndexes(String schema, String tableName, boolean unique, boolean approximate) Builds a valid result set of the description of the given table's indices and statistics.
CassandraMetadataResultSet	buildPrimaryKeys(String schema, String tableName) Builds a valid result set of the description of the given table's primary key columns.
CassandraMetadataResultSet	buildTables(String schemaPattern, String tableNamePattern) Builds a valid result set of the description of the tables available in the given catalog (Cassandra cluster).
CassandraMetadataResultSet	buildTableTypes() Builds a valid result set of the table types available in Cassandra database.

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

TableMetadataResultSetBuilder

public TableMetadataResultSetBuilder(CassandraStatement statement)
                              throws SQLException

Constructor.

Parameters:

statement - The statement.

Throws:

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

Method Detail

buildTableTypes

public CassandraMetadataResultSet buildTableTypes()
                                           throws SQLException

Builds a valid result set of the table types available in Cassandra database. This method is used to implement the method DatabaseMetaData.getTableTypes().

The columns of this result set are:

1. TABLE_TYPE String => table type: always .

Returns:

A valid result set for implementation of DatabaseMetaData.getTableTypes().

Throws:

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

buildTables

public CassandraMetadataResultSet buildTables(String schemaPattern,
                                              String tableNamePattern)
                                       throws SQLException

Builds a valid result set of the description of the tables available in the given catalog (Cassandra cluster). This method is used to implement the method DatabaseMetaData.getTables(String, String, String, String[]).

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

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. TABLE_TYPE String => table type: always here.
5. REMARKS String => explanatory comment on the table.
6. TYPE_CAT String => the types catalog: always null here.
7. TYPE_SCHEM String => the types schema: always null here.
8. TYPE_NAME String => type name: always null here.
9. SELF_REFERENCING_COL_NAME String => name of the designated "identifier" column of a typed table: always null here.
10. REF_GENERATION String => specifies how values in SELF_REFERENCING_COL_NAME are created: always null 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.

Returns:

A valid result set for implementation of DatabaseMetaData.getTables(String, String, String, String[]).

Throws:

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

buildIndexes

public CassandraMetadataResultSet buildIndexes(String schema,
                                               String tableName,
                                               boolean unique,
                                               boolean approximate)
                                        throws SQLException

Builds a valid result set of the description of the given table's indices and statistics. This method is used to implement the method DatabaseMetaData.getIndexInfo(String, String, String, boolean, boolean).

Only indexes of the table exactly matching the catalog, schema and table name are returned. They are ordered by NON_UNIQUE, TYPE, INDEX_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. NON_UNIQUE boolean => Can index values be non-unique, false when TYPE is DatabaseMetaData.tableIndexStatistic. Always true here.
5. INDEX_QUALIFIER String => index catalog, null when TYPE is DatabaseMetaData.tableIndexStatistic.
6. INDEX_NAME String => index name, null when TYPE is DatabaseMetaData.tableIndexStatistic.
7. TYPE short => index type:
   • DatabaseMetaData.tableIndexStatistic - this identifies table statistics that are returned in conjunction with a table's index descriptions
   • DatabaseMetaData.tableIndexClustered - this is a clustered index
   • DatabaseMetaData.tableIndexHashed - this is a hashed index
   • DatabaseMetaData.tableIndexOther - this is some other style of index
   Always DatabaseMetaData.tableIndexHashed here.
8. ORDINAL_POSITION short => column sequence number within index; zero when TYPE is DatabaseMetaData.tableIndexStatistic. Always 1 here.
9. COLUMN_NAME String => column name, null when TYPE is DatabaseMetaData.tableIndexStatistic.
10. ASC_OR_DESC String => column sort sequence, "A" means ascending, "D" means descending, may be null if sort sequence is not supported or when TYPE is DatabaseMetaData.tableIndexStatistic. Always null here.
11. CARDINALITY int => When TYPE is DatabaseMetaData.tableIndexStatistic, then this is the number of rows in the table; otherwise, it is the number of unique values in the index. Always -1 here.
12. PAGES int => When TYPE is DatabaseMetaData.tableIndexStatistic, then this is the number of pages used for the table; otherwise, it is the number of pages used for the current index. Always -1 here.
13. FILTER_CONDITION String => Filter condition, if any: always null here.

Parameters:

schema - A schema name. 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 down the search.

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

unique - when true, return only indices for unique values; when false, return indices regardless of whether unique or not. This parameter has no effect here.

approximate - when true, result is allowed to reflect approximate or out of data values; when false, results are requested to be accurate. This parameter has no effect here.

Returns:

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

Throws:

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

buildPrimaryKeys

public CassandraMetadataResultSet buildPrimaryKeys(String schema,
                                                   String tableName)
                                            throws SQLException

Builds a valid result set of the description of the given table's primary key columns. This method is used to implement the method DatabaseMetaData.getPrimaryKeys(String, String, String).

Only primary keys of the table exactly matching the catalog, schema and table name are returned. They are ordered by COLUMN_NAME.

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. KEY_SEQ short => sequence number within primary key (a value of 1 represents the first column of the primary key, a value of 2 would represent the second column within the primary key).
6. PK_NAME String => primary key name: always null here.

Parameters:

schema - A schema name. 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 down the search.

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

Returns:

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

Throws:

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

buildBestRowIdentifier

public CassandraMetadataResultSet buildBestRowIdentifier(String schema,
                                                         String table,
                                                         int scope)
                                                  throws SQLException

Builds a valid result set of the description of a table's optimal set of columns that uniquely identifies a row. This method is used to implement the method DatabaseMetaData.getBestRowIdentifier(String, String, String, int, boolean).

In Cassandra, all the tables must define a single primary key and the columns defining this primary key ensure the uniqueness of each row. So, we consider in this implementation that the best row identifier for a table is always its primary key regardless of the specified scope. Also, the parameter nullable has no effect here since Cassandra does not allow null values in primary keys.

Only identifiers for tables matching the catalog, schema and table name criteria are returned. They are ordered by SCOPE.

The columns of this result set are:

1. SCOPE short => actual scope of result:
   • DatabaseMetaData.bestRowTemporary - very temporary, while using row
   • DatabaseMetaData.bestRowTransaction - valid for remainder of current transaction
   • DatabaseMetaData.bestRowSession - valid for remainder of current session
   Always the input scope value.
2. COLUMN_NAME String => column name.
3. DATA_TYPE int => SQL type from Types.
4. TYPE_NAME String => Data source dependent type name, for a UDT the type name is fully qualified.
5. COLUMN_SIZE int => column size.
6. BUFFER_LENGTH int => not used: always 0 here.
7. DECIMAL_DIGITS int => the number of fractional digits, null is returned for data types where it is not applicable. Always null here.
8. PSEUDO_COLUMN short => is this a pseudo column like an Oracle ROWID:
   • DatabaseMetaData.bestRowUnknown - may or may not be pseudo column
   • DatabaseMetaData.bestRowNotPseudo - is not a pseudo column
   • DatabaseMetaData.bestRowPseudo - is a pseudo column
   Always DatabaseMetaData.bestRowNotPseudo here since there is no concept of pseudo column in Cassandra.

Parameters:

schema - 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.

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

scope - The scope of interest, using the same values as SCOPE in the result set.

Returns:

A valid result set for implementation of DatabaseMetaData.getBestRowIdentifier(String, String, String, int, boolean).

Throws:

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