org.apache.nifi.processors.standard.db

Interface DatabaseAdapter

All Known Implementing Classes:

GenericDatabaseAdapter, MSSQL2008DatabaseAdapter, MSSQLDatabaseAdapter, MySQLDatabaseAdapter, Oracle12DatabaseAdapter, OracleDatabaseAdapter, PhoenixDatabaseAdapter, PostgreSQLDatabaseAdapter

public interface DatabaseAdapter

Interface for RDBMS/JDBC-specific code.

Method Summary

Modifier and Type	Method and Description
String	getDescription()
String	getName()
String	getSelectStatement(String tableName, String columnNames, String whereClause, String orderByClause, Long limit, Long offset) Returns a SQL SELECT statement with the given clauses applied.
default String	getSelectStatement(String tableName, String columnNames, String whereClause, String orderByClause, Long limit, Long offset, String columnForPartitioning) Returns a SQL SELECT statement with the given clauses applied.
default String	getTableAliasClause(String tableName)
default String	getUpsertStatement(String table, List<String> columnNames, Collection<String> uniqueKeyColumnNames) Returns an SQL UPSERT statement - i.e.
default boolean	supportsUpsert() Tells whether this adapter supports UPSERT.
default String	unwrapIdentifier(String identifier) Returns a bare identifier string by removing wrapping escape characters from identifier strings such as table and column names.

Method Detail

getName

String getName()

getDescription

String getDescription()

getSelectStatement

String getSelectStatement(String tableName,
                          String columnNames,
                          String whereClause,
                          String orderByClause,
                          Long limit,
                          Long offset)

Returns a SQL SELECT statement with the given clauses applied.

Parameters:

tableName - The name of the table to fetch rows from

columnNames - The names of the columns to fetch from the table

whereClause - The filter to apply to the statement. This should not include the WHERE keyword

orderByClause - The columns/clause used for ordering the result rows. This should not include the ORDER BY keywords

limit - The value for the LIMIT clause (i.e. the number of rows to return)

offset - The value for the OFFSET clause (i.e. the number of rows to skip)

Returns:

A String containing a SQL SELECT statement with the given clauses applied

getSelectStatement

default String getSelectStatement(String tableName,
                                  String columnNames,
                                  String whereClause,
                                  String orderByClause,
                                  Long limit,
                                  Long offset,
                                  String columnForPartitioning)

Returns a SQL SELECT statement with the given clauses applied. Note that if this method is overridden, the other overloaded methods need to be overridden as well, to call this method with columnForPartitioning = false

Parameters:

tableName - The name of the table to fetch rows from

columnNames - The names of the columns to fetch from the table

whereClause - The filter to apply to the statement. This should not include the WHERE keyword

orderByClause - The columns/clause used for ordering the result rows. This should not include the ORDER BY keywords

limit - The value for the LIMIT clause (i.e. the number of rows to return)

offset - The value for the OFFSET clause (i.e. the number of rows to skip)

columnForPartitioning - The (optional) column name that, if provided, the limit and offset values are based on values from the column itself (rather than the row number)

Returns:

A String containing a SQL SELECT statement with the given clauses applied

supportsUpsert

default boolean supportsUpsert()

Tells whether this adapter supports UPSERT.

Returns:

true if UPSERT is supported, false otherwise

getUpsertStatement

default String getUpsertStatement(String table,
                                  List<String> columnNames,
                                  Collection<String> uniqueKeyColumnNames)

Returns an SQL UPSERT statement - i.e. UPDATE record or INSERT if id doesn't exist.

There is no standard way of doing this so not all adapters support it - use together with supportsUpsert()!

Parameters:

table - The name of the table in which to update/insert a record into.

columnNames - The name of the columns in the table to add values to.

uniqueKeyColumnNames - The name of the columns that form a unique key.

Returns:

A String containing the parameterized jdbc SQL statement. The order and number of parameters are the same as that of the provided column list.

unwrapIdentifier

default String unwrapIdentifier(String identifier)

Returns a bare identifier string by removing wrapping escape characters from identifier strings such as table and column names.

The default implementation of this method removes double quotes. If the target database engine supports different escape characters, then its DatabaseAdapter implementation should override this method so that such escape characters can be removed properly.

Parameters:

identifier - An identifier which may be wrapped with escape characters

Returns:

An unwrapped identifier string, or null if the input identifier is null

getTableAliasClause

default String getTableAliasClause(String tableName)