com.ing.data.cassandra.jdbc.metadata

Class FunctionMetadataResultSetBuilder

java.lang.Object

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

com.ing.data.cassandra.jdbc.metadata.FunctionMetadataResultSetBuilder

public class FunctionMetadataResultSetBuilder
extends AbstractMetadataResultSetBuilder

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

Constructor Summary

Constructors

Constructor and Description
FunctionMetadataResultSetBuilder(CassandraStatement statement) Constructor.

Method Summary

Modifier and Type	Method and Description
CassandraMetadataResultSet	buildFunctionColumns(String schemaPattern, String functionNamePattern, String columnNamePattern) Builds a valid result set of the given catalog's system or user function parameters and return type.
CassandraMetadataResultSet	buildFunctions(String schemaPattern, String functionNamePattern) Builds a valid result set of the system and user functions 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

FunctionMetadataResultSetBuilder

public FunctionMetadataResultSetBuilder(CassandraStatement statement)
                                 throws SQLException

Constructor.

Parameters:

statement - The statement.

Throws:

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

Method Detail

buildFunctions

public CassandraMetadataResultSet buildFunctions(String schemaPattern,
                                                 String functionNamePattern)
                                          throws SQLException

Builds a valid result set of the system and user functions available in the given catalog (Cassandra cluster). This method is used to implement the method DatabaseMetaData.getFunctions(String, String, String).

Only system and user function descriptions matching the schema and function name criteria are returned. They are ordered by FUNCTION_CAT, FUNCTION_SCHEM, FUNCTION_NAME and SPECIFIC_NAME.

The columns of this result set are:

1. FUNCTION_CAT String => function catalog, may be null: here is the Cassandra cluster name (if available).
2. FUNCTION_SCHEM String => function schema, may be null: here is the keyspace the table is member of.
3. FUNCTION_NAME String => function name. This is the name used to invoke the function.
4. REMARKS String => explanatory comment on the function (always empty, Cassandra does not allow to describe functions with a comment).
5. FUNCTION_TYPE short => kind of function:
   • DatabaseMetaData.functionResultUnknown - cannot determine if a return value or table will be returned
   • DatabaseMetaData.functionNoTable - does not return a table (Cassandra user-defined functions only return CQL types, so never a table)
   • DatabaseMetaData.functionReturnsTable - returns a table
6. SPECIFIC_NAME String => the name which uniquely identifies this function within its schema. This is a user specified, or DBMS generated, name that may be different then the FUNCTION_NAME for example with overload functions.

A user may not have permission to execute any of the functions that are returned by getFunctions.

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 down the search.

functionNamePattern - A function name pattern; must match the function name as it is stored in the database.

Returns:

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

Throws:

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

buildFunctionColumns

public CassandraMetadataResultSet buildFunctionColumns(String schemaPattern,
                                                       String functionNamePattern,
                                                       String columnNamePattern)
                                                throws SQLException

Builds a valid result set of the given catalog's system or user function parameters and return type. This method is used to implement the method DatabaseMetaData.getFunctionColumns(String, String, String, String).

Only descriptions matching the schema, function and parameter name criteria are returned. They are ordered by FUNCTION_CAT, FUNCTION_SCHEM, FUNCTION_NAME and SPECIFIC_NAME. Within this, the return value, if any, is first. Next are the parameter descriptions in call order. The column descriptions follow in column number order.

The columns of this result set are:

1. FUNCTION_CAT String => function catalog, may be null: here is the Cassandra cluster name (if available).
2. FUNCTION_SCHEM String => function schema, may be null: here is the keyspace the table is member of.
3. FUNCTION_NAME String => function name. This is the name used to invoke the function.
4. COLUMN_NAME String => column/parameter name.
5. COLUMN_TYPE short => kind of column/parameter:
   • DatabaseMetaData.functionColumnUnknown - unknown type
   • DatabaseMetaData.functionColumnIn - IN parameter
   • DatabaseMetaData.functionColumnInOut - INOUT parameter
   • DatabaseMetaData.functionColumnOut - OUT parameter
   • DatabaseMetaData.functionReturn - function return value
   • DatabaseMetaData.functionColumnResult - indicates that the parameter or column is a column in the ResultSet
6. DATA_TYPE int => SQL data type from Types.
7. TYPE_NAME String => SQL type name, for a UDT type the type name is fully qualified.
8. PRECISION int => maximum precision.
9. LENGTH int => length in bytes of data.
10. SCALE int => scale, null is returned for data types where SCALE is not applicable.
11. RADIX short => precision radix.
12. NULLABLE short => can you use NULL for this type:
    • DatabaseMetaData.typeNoNulls - does not allow NULL values
    • DatabaseMetaData.typeNullable - allows NULL values
    • DatabaseMetaData.typeNullableUnknown - nullability unknown
13. REMARKS String => comment describing column/parameter (always empty, Cassandra does not allow to describe columns with a comment).
14. CHAR_OCTET_LENGTH int => the maximum length of binary and character based parameters or columns. For any other datatype the returned value is a NULL.
15. ORDINAL_POSITION int => the ordinal position, starting from 1, for the input and output parameters. A value of 0 is returned if this row describes the function's return value. For result set columns, it is the ordinal position of the column in the result set starting from 1.
16. IS_NULLABLE String => "YES" if a parameter or column accepts NULL values, "NO" if not and empty if the nullability is unknown.
17. SPECIFIC_NAME String => the name which uniquely identifies this function within its schema. This is a user specified, or DBMS generated, name that may be different then the FUNCTION_NAME for example with overload functions.

The PRECISION column represents the maximum column size that the server supports for the given datatype. For numeric data, this is the maximum precision. For character data, this is the length in characters. For datetime data types, this is the length in characters of the String representation (assuming the maximum allowed precision of the fractional seconds component). For binary data, this is the length in bytes. For the ROWID datatype (not supported by Cassandra), this is the length in bytes. The value null is returned for data types where the column size is not applicable.

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 down the search.

functionNamePattern - A function name pattern; must match the function name as it is stored in the database.

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

Returns:

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

Throws:

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