This package contains the classes that represent the commands that the NanoSQL database recognizes. All of the commands are represented as subclasses of the
Commandabstract base-class. Commands are grouped into the following categories:
Data Definition Language (DDL) CommandsThese commands manipulate the contents of the data-dictionary. The supported commands are as follows:
Data Manipulation Language (DML) CommandsThese commands retrieve and modify the database tables themselves. Note that these commands all derive from the
QueryCommandabstract class. The supported commands are as follows:
- DELETE ... -
- INSERT ... -
- SELECT ... -
- UPDATE ... -
Transaction-Demarcation CommandsThese commands provide control over when a transaction is started or ended:
- BEGIN [WORK] | START TRANSACTION -
- COMMIT [WORK] -
- ROLLBACK [WORK] -
Utility CommandsThese commands perform various utility operations:
Class Summary Class Description AnalyzeCommandThis Command class represents the ANALYZE SQL command, which analyzes a table's internal data and updates its cached statistics to be as up-to-date as possible. BeginTransactionCommandThis class represents a command that starts a transaction, such as BEGIN, BEGIN WORK, or START TRANSACTION. CommandAbstract base-class for all commands that NanoDB supports. CommandPropertiesThis class holds properties that might contain additional details for a command. CommitTransactionCommandThis class represents a command that commits a transaction, such as COMMIT or COMMIT WORK. ConstraintDeclConstraints may be specified at the table level, or they may be specified on individual columns. CrashCommandThis command "crashes" the database by shutting it down immediately without any proper cleanup or flushing of caches. CreateIndexCommandThis command-class represents the CREATE INDEX DDL command. CreateTableCommandThis command handles the CREATE TABLE DDL operation. CreateViewCommandThis command-class represents the CREATE VIEW DDL command. DDLUtilsThis helper class provides some useful functions for constructing keys and indexes and other details for tables that are being initialized. DeleteCommandThis command object represents a top-level DELETE command issued against the database. DeleteCommand.TupleRemoverAn implementation of the tuple processor interface used by the
DeleteCommandto delete each tuple.
DropIndexCommandThis command-class represents the DROP INDEX DDL command. DropTableCommandThis Command class represents the DROP TABLE SQL command. DumpCommandAn abstract base-class that holds the common implementation of the various kinds of dump commands. DumpCommand.TupleExporterA tuple processor implementation used to dump each tuple. DumpIndexCommandThis command object represents a DUMP INDEX command issued against the database. DumpTableCommandThis command object represents a DUMP TABLE command issued against the database. ExitCommandThis Command class represents the EXIT or QUIT SQL commands. ExplainCommandThis Command class represents the EXPLAIN SQL command, which prints out details of how SQL DML statements will be evaluated. FlushCommandThis command flushes all unwritten data from the buffer manager to disk. InsertCommandThis command object represents a top-level INSERT command issued against the database. InsertCommand.TupleInserterAn implementation of the tuple processor interface used by the
InsertCommandto insert tuples into a table, when the command is of the form INSERT ...
OptimizeCommandThis Command class represents the OPTIMIZE SQL command, which optimizes a table's representation (along with any indexes) to improve access performance and space utilization. QueryCommandThis class represents all SQL query commands, including SELECT, INSERT, UPDATE, and DELETE. RollbackTransactionCommandThis class represents a command that rolls back a transaction, such as ROLLBACK or ROLLBACK WORK. SelectCommandThis command object represents a top-level SELECT command issued against the database. SetPropertyCommandImplements the "SET VARIABLE ..." command. ShowPropertiesCommandImplements the "SHOW VARIABLES" command. ShowSystemStatsCommandImplements the "SHOW [system] STATS" command. ShowTablesCommandImplements the "SHOW TABLES" command. ShowTableStatsCommandImplements the "SHOW TABLE t STATS" command. TableColumnDeclThis class represents a single column declaration within a CREATE TABLE command. UpdateCommandThis command object represents a top-level UPDATE command issued against the database. UpdateCommand.TupleUpdaterAn implementation of the tuple processor interface used by the
UpdateCommandto update each tuple.
UpdateValueThis class represents a single column-name/expression pair in an UPDATE statement's SET clause. VerifyCommandThis Command class represents the VERIFY SQL command, which verifies a table's representation (along with any indexes) to ensure that all structural details are valid.
Enum Summary Enum Description Command.TypeCommands are either Data-Definition Language (DDL), Data-Manipulation Language (DML), or utility commands. QueryCommand.TypeTypesafe enumeration of query-command types.
Exception Summary Exception Description ExecutionExceptionThis exception is thrown when a fatal error occurs during command execution.