- die definierten Begriffen camelNotation accessPath für access path, weil wir in den Schlüsselwörtern keine Spaces wollen
- aus irgendeiner Wiki Seite kann mit {lia+A.Glo#clustering} ⇒ clustering auf irgend ein Schlüsselwort des Glossars verwiesen werden
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accessPath = Zugriffspfad. Der Zugriffsphad und die Methode für den Zugriff auf die gewünschten Daten. DB2 verwendet eine Reihe verschiedener Methoden, effiziente aber auch ineffiziente.
aggregateFunction = Eine Funktion welche ein Resultat gewinnt aus den Werten in einer oder in mehreren Rows. Siehe dagegen unter Scalar Function.
alias In DB2, an alternative name that you can use in SQL statement to refer to a table or a view in the local or remote DB2 subsystem. An alias can be accessed by users other than its creator. When a table is dropped, its aliased are retained. In a distributed database environment, aliases are useful for giving a short, local name to a remote table.
ambiguousCursor = A database cursor that is in a plan or package that contains either PREPARE or EXECUTE IMMEDIATE SQL statements, and for which the following statements are true: the cursor is not defined with the FOR READ ONLY clause or the FOR UPDATE OF clause; the cursor is not defined on a read-only result table; the cursor is not the target of a WHERE CURRENT clause on an SQL UPDATE or DELETE statement.
APAR = authorized program analysis report = von IBM anerkannter Programmfehler. An APAR is formally tracked until a solution is provided. The APAR is given a unique number for tracking and a target date for solution durch einen PTF.
asynchronousIO Read or write operations that are executed separately from the thread that requested them, by a read or write agent running parallel, allowing application processing to continue while the I/O activity occurs.
automaticQueryRewrite = A process that examines an SQL statement that refers to one or more base tables, and, if appropriate, rewrites the query so that it performs better. This process can also determine whether to rewrite a query so that it refers to one or more materialized query tables that are derived from the source tables.
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bind A process that determine access paths to the data selected through SQL statements. In DB2, the BIND command performs the bind function to create an application plan or a package. The BIND process uses the results of the DB2 precompiler (contained in a DBRM) as input to the DB2 optimizer.
BSDS = Bootstrap data set. A VSAM data set used by DB2 to control DB2 log data sets and manage an inventory of those logs. The BSDS is also used to record the image copy backup taken for the SYSIBM.SYSCOPY DB2 Catalog table.
bufferPool = An area of storage in which the buffers for one or more tablespaces and indexes are kept.
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catalog System Catalog. In a relational database, a collection of tables that contain descriptions and statistics for every object in the database, such as tables, views, and indexes. Alternate Catalog Mapping provides a mechanism for defining shadow tables or views for the DB2 system catalog tables. These shadow tables can increase performance by reducing contention on the DB2 catalog. Bei CS werden keine Shadow Catalog Tables verwendet, da heute die Performance des originalen Catalog kein Problem mehr darstellt.
Checkpoint at checkpoint time, all updated pages in the virtual buffer pool that are on the deferred write queue are written to DASD. Ein checkpoint wird nach bestimmten anzahl LogRecords oder Minuten ausgelöst und schreibt folgendens ins Log:
- Unit of Recovery Summary (alle offen Transaktionen)
- Page Set Summay (offene Pagesets und RestartPunkt
- Page Set Exception Summary
- Page Set UR Summary Record: welche PageSets wurden von aktiven Transaktion verändert
childTable = child table Synonym dependent table. A table containing a foreign key that references the primary key in a parent table.
CICS = Customer Information Control System . An IBM licensed program that provides online transaction processing services and management for critical business applications. CICS runs on many IBM and non-IBM platforms (from the desktop to the mainframe) and is used in various types of networks that range in size from a few terminals to many thousands of terminals. The CICS application programming interface (API) enables programmers to port applications among the hardware and software platforms on which CICS is available. Each product in the CICS family can interface with the other products in the CICS family, thus enabling interproduct communication.
client. entweder
- The requesting program in a client/server model.\\, oder
- A computer that accessed shared resources provided by another computer (server).
clustering = Physische Ablage der Rows in einer Tabelle nach einem Ordnungskriterium, d.h. die Rows werden sortiert abgelegt. DB2 versucht, diese Reihenfolge so gut als möglich aufrecht zu erhalten. Zugriffe auf derart angeordnete Daten sind schneller für einige Operationen, besonders für grouping, ordering, and Vergleiche. Das Clustering wird durch einen Index kontrolliert. Es kann nur eine Clustering Sequenz verwendet werden pro Tabelle. Die Clustering Sequenz wird durch die REORG Utility (wieder) etabliert. Wird die Tabelle mit LOAD geladen, so muss bereits das Input File in der gewünschten Reihenfolge sortiert sein.
clusteringIndex = An index that determines how rows are physically ordered (clustered) in a table space. If a clustering index on a partitioned table is not a partitioning index, the rows are ordered in cluster sequence within each data partition instead of spanning partitions. Prior to Version 8 of DB2 UDB for z/OS, the partitioning index was required to be the clustering index.
collection A logical grouping of packages that have the same qualifier. A collection is created the first time that you bind a package using a collection name.
column In a relational database, the vertical component of a table. The column is equivalent to a field in a non-relational system.
columnFunction = An operation that is applied to a group of rows and that returns a single value result for a designated column.
commit = The operation that ends a work unit by releasing locks an recording that work unit’s updates in an active log data set. Once a commit is performed, other users and applications can use the updates.
consistencyToken = An identifier used to match a DBRM with the plan or package to which the DBRM is bound. A consistency token mar or may not be a timestamp.
CT = Cursor tables or copies of the SKCTs
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dataSharing = The ability of multiple DB2 subsystems to have concurrent read/write access to the same data.
dataType = A definition for the set of data that can be stored in a column. The data type termines the range of valid values for the set, the operations that can be performed on the set, and the way in which the data is stored.
database = In DB2 a collection of {lia#tablespace}s. Generally, a collection of data structured so that users can access, update, or add to the data. A relational database holds data in a collection of tables or in a collection of tablespaces and indexspaces.
databaseAccessThread = thread created on behalf of a remote DBMS to access data at the local subsystem.
databaseServer = The node on a network that stores a shared database and administers database requests sent by client workstations.
DB = database. In DB2 a collection of {lia#TS}s. Generally, a collection of data structured so that users can access, update, or add to the data. A relational database holds data in a collection of tables or in a collection of tablespaces and indexspaces.
DBA = database administrator. The person in charge of designing, protecting, and maintaining a database.
DBID = database identifier. Interne Nummer eine DB
DBMS = database management system. system that controls the creation and maintenance of a database and access to the data within the database. A sample DBMS is DB2.
DBRM = database request module. A data set member created by the DB2 precompiler. It contains SQL statements extracted from a source program. These extracted statements are then used as input to bind process.
DCL = Data Control Language, a language that uses GRANT and REVOKE statements to control security in a database.
DDF = Distributed Data Facility: die Db2 Subkomponente für verteilten Zugriff und Transaktionen.
DDBMS = Distributed database management system, a system that allows a single application to run transparently on data found in different databases. Thes databases can run on various platform types and be connected by different network communications.
DDF = Distributed Data Facility. It enables processing between distributed DB2 subsystems.
DDL = Data Definition Language. A language used to define elements in a database, such as row layout, column definitions, and key columns.
DFSMS = Data Facility Storage Management Subsystem. An IBM licensed program that provides storage, data, and device management functions. It's main use for DB2 is that SMS can do the dataset placement on disk subsystems for DB2 tablespace datasets.
directory In DB2, a system database containing information on programs and queries executing within a subsystem. The directory is not directly accessible to the user.
distributedDatabase
- A database that is physically decentralized. However, the DBMS handles the database in such a way that the user has a centralized view of the database for access and query purposes.
### A database that is controlled by a single DBMS, but is dispersed over multiple nodes on a network.
- A database that is physically decentralized. However, the DBMS handles the database in such a way that the user has a centralized view of the database for access and query purposes.
DM = Data Manager, die subcomponent für physische Record Manipulationen.
DML = Data Manipulation Language, a language that provides statements used to access and modify data in a database.
Zum Beispiel SQL mit Statements wie SELECT, INSERT, UPDATE and DELETE.
DRDA = Distributed Relational Database Architecture (DRDA) wird sowohl die IBM-Architektur für verteilte Datenbanken bezeichnet, die sich auf unterschiedlichen heterogenen Plattformen befinden, als auch das von IBM für die Verteilung der Daten entwickelte Protokoll, Ablösung von private protocoll
dynamicSQL = SQL statements that can be changed during a program’s execution, or that are entered at a terminal and executed in real time.
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editProc = A program used to provide data compression in DB2. An EDITPROC is associated with a table when the table is created.
encryption = A way of protecting data from unauthorized viewing or use by scrambling the data until it is indecipherable. If encrypted data is retrievable, you can decipher it only through a decoding process.
EDMPool = Environmental Descriptor Manager Pool besteht aus
EDM DBD cache für DBDs
Authorization cache block for each plan, except one with CACHESIZE set to 0
EDM statement cache Skeletons of dynamic SQL for CACHE DYNAMIC SQL
EREP = Environmental Record Editing and Printing Program. A program that makes the data contained in the system recorder file available for further analysis.
explain In DB2, a command that is executed on an SQL statement or an application plan to provide information about the access paths chosen during a bind.
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foreignKey = A column or combination of columns (in as childTable) whose values reference a primary key in the same table or another table (the parentTable.
freeSpace = The total unused space in a page. Unused space refers to space currently not used to store records or control information.
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GTF = Generalized Trace Facility: z/OS Feature, kann als Destination für DB2 Traces verwendet werden Main.SMF0022
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headerPage = A page containing control information about a page set. In DB2 the header page includes the internal object file identifier and the internal database identifier of the tablespace and database maintained in the page set.
holeSpace = The total number of bytes of space on a data page once rows are deleted. Hole space is reclaimed after a reorg utility is run.
hostVariable = Eine im Programmsource der Hostsprache (z.B. PL/1) deklarierte Variable, welche in einem SQL Statement verwendet wird. Dies erlaubt dem Programm, das SQL Statement mit wechselndem Dateninhalt auszuführen. Variablen können auch zu Strukturen zusammengefasst werden. In SQL Statements muss den Variablennamen ein Doppelunkt vorangestellt werden.
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imageCopy = Eine Sicherungskopie eines TSTablespace, welche entweder alle oder nur die geänderten Datapages enthält, auf einem sequentuiellen File. Diese Kopien werden vom DB2 Recovery System verwendet, um defekte Tablespaces wiederherzustellen.
index = A balanced tree structure that orders the values of columns in a table. You can index a table by one or more of its columns, enabling you to search for data more directly and efficiently.
indexPage = A page containing index rows.
indexable The type of predicate within an SQL statement that is written in a format that will allow DB2 to use an index to access data.
indexControlledPartitioning = A type of partitioning in which partition boundaries for a partitioned table are controlled by values that are specified on the CREATE INDEX statement. Partition limits are saved in the LIMITKEY column of the SYSIBM.SYSINDEXPART catalog table. Wir stellen konsequent auf tablebasedPartitioning um.
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join = In SQL, an operation that retrieves data from two or more tables, and that is based on matching values in ore or more columns within these tables.
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latch ähnlich wie ein lock, aber billiger.
leafPage = The index page that contains pointers to actual data rows in a table. Non-leaf page, an index page that contains pointers to leaf pages or other non-leaf pages within the index hierarchy. Non-leaf pages never point to data rows.
levelID Db2 schreibt regelmässig (alle n Checkpoints gemäss zParm DLDFREQ = levelID update freq) in die HeaderPage (HPGLEVEL bzw. HPGPELFL) jedes PageSets den aktuellen Timestamp. Wenn die gelesene levelID nicht der erwarteten entspricht, wird ein down-level Fehler erzeugt.
lock A mechanism that controls the situation of multiple users accessing and updating the same data at the same time.
log = A collection of records that describe the activities of a DBMS, such as DML or utility execution. The log is used for object or system recovery in the event of an error.
lpar = Logical Partition. A subset of a single system that contains resources (processors, memory, and input/output devices). A logical partition operates as an independent system. If hardware requirements are met, multiple logical partitions can exist within a system.
LRSN = Log record sequence number. a generated number that is used to reference a specific log record, enthält einen Zeitpunkt. Similar to RBA, the LRSN is used in a data-sharing environment to reference the log record and identify which DB2 subsystem generated the log record.
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mirrorTable = A table that is duplicated at multiple sites. The table contains redundant data to eliminate the need for distributed requests.
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normalization = The process of transforming conceptual entities and related data elements into table structures.
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object : In Db2 an item that can be created and managed using SQL, such as databases, tablespaces, tables, indexes, and views.
optimizer = The DB2 optimizer is responsible for choosing the most efficient access path to the data. For static SQL, the access path is evaluated and determined at bind time, for dynamic SQL at execution time.
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package = A non-executable program containing optimized access path logic for a single DBRM. You must then bind the package into a plan before it can be executed with an application program.
pageSet = A physical grouping of pages. The page set contains a header page, space map pages, and data pages.
partitionedTablespace = A tablespace divided into separate components, each component residing in a separate data set. Partitioned tablespaces can increase the availability of data in large tables.
plan = application plan : Executable logic representing the access paths to data that is selected through SQL statements. This logic is the result of a bind process. The database will use this plan to process SQL statements encountered when the statements are executed during a program.
PLAN_TABLE In DB2, the table used to hold the results of an explain.
PMR = Problem Management Record = Fehlermeldung an IBM. A PMR is created when a customer submits a request to fix a software problem via Electronic Service Request (ESR / SR). A PMR number is assigned to track the request. A PMR is also referred to as a problem report. A PMR number is also referred to as a report number. Daraus können APARs und PTFs entstehen.
predicate = a search condition that is either true, false, or unknown about a specific row or group of rows.
primaryKey = A unique, non-null column or combination of columns in a table definition. This key distinguishes each row from all other rows in the table. A parent table must have a primary key.
privateProtocol = älteres Protokoll für distributed Db Access, wird ersetzt durch A.Glo: Db2 Glossar
PT = Package Tables, or copies of the SKPTs
PTF = program temporary fix (von IBM). When applied, will temporarily solve the problem for the customer. The PTF will “close” the APAR. PTFs can be applied individually but as part of a fix package. Development entscheidet wie der PTF in den nächsten Release eingebaut wird.
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query = A request for database information based on certain conditions. SQL statements are a means of creating queries.
quiesce = A utility that clears the rows from DB2 buffers and writes them to disk. It also creates a recovery RBA record to the active log.
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RBA = Relative byte address. An address that describes the location of a DB2 recovery point relative to the beginning of the log.
RDS = Relational Data System, die Db2 Subkomponente für relationale DB-Operationen
rebind = The process of binding an application program that was previously bound. The resulting new application plan takes into account any new or updated objects in the database.
RI =referential integrity = The means of ensuring that data is updated properly between tables that are related by primary and foreign keys. For example, a new foreign key value cannot exist until related primary key columns is updated with this value. Ensuring referential integrity requires constraints for inserting, updating, and deleting data in tables.
relationalDatabase = A database that stores information in tables and searches for data by using the data in certain columns of one table to locate additional data in other tables.
RID = Row ID, the internal address of a row. Es gibt 4 und 5 Byte RID-Formate, im letzten Byte ist die Adresse der Row innerhalt der Page, die vorangehenden Bytes enthalte die Adresse der page, inklusive der PartitionsNummer.
rollback = The process of restoring data changed by SQL statements to its state at the time of the last commit. This process is the opposite of a commit.
rootPage : The highest page level in an index. The root page follows the space map page in a page set. It can be structured as either a leaf page or non-leaf page, depending on the number of entries in the index.
row = A horizontal component of a table, containing a value for each column. A row is synonymous with a record.
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scalarFunction = An SQL operation that produces a single value from another value and is expressed as a function name, followed by a list of arguments that are enclosed in parentheses. Contrast with aggregate function.
searchArgument = A specific WHERE clause containing a search condition that will improve performance.
segmentedTablespace = Ein DB2 TS, welcher eine oder mehrere Tabellen enthalten kann. Mehrere Data pages - bei uns üblicherweise 64 - werden zu gleich grossen Segmenten zusammengefasst. Jedes Segment, und damit auch jede Data Page kann nur Rows von einer einzigen Tabelle enthalten. Da Rows von unterschiedlichen Tabellen nicht gemischt sind, ist gleichzeitiger Zugriff auf mehrere Tabellen kein Problem. Dieser Tablespace Typ sollte heute (2006) ausschliesslich verwendet werden, wenn nicht Partitionen eingesetzt werden sollen.
server
- The answering program in a client/server model.
- The computer that makes resources available to computers acting as workstations in a network (clients). The server can be a stand-alone PC, or a mainframe.
shadowTable = A copy of a system catalog table. Using shadow tables help to eliminate contention on the actual system catalog tables.
simpleTablespace = Ein DB2 Tablespace, welcher eine oder mehrere Tabellen enthalten kann. Jede Data Page kann Rows von mehreren Tabellen enthalten. Dieser Tablespace Typ sollte heute (2006) wegen Schwächen in der Spaceverwaltung nicht mehr verwendet werden. Ab DB2 9 (2009) können solche tablespaces nicht mehr neu angelegt werden. Es ist zu erwarten, dass der Support ganz entfallen wird.
SMS ??? sieht DFSMS
SQL = Structured query language, a database language used to query, modify, and manage relational databases.
stage1Predicate = SQL-Prädikate, die vom DM ausgeführt werden, siehe man#PerTun properties of predicates
stage2Predicate = Stage 2 Predicates sind SQL-Prädikate, die vom RDS ausgeführt werden, siehe man#PerTun properties of predicates
statistics = Information found in the database catalog that an optimizer or bind process uses to determine the most efficient access paths to data. Statistics include information such as the number of rows for a table, the percentage in clustering order, and the number of pages used by a table.
storageGroup= An object used to identify a set of DASD volumes on which DB2 information can be stored.
storedProcedure = A collection of SQL statements that are to be executed by name. Thes statements are not event-driven.
subcomponent Unterkomponente eines Db2 Subsystems. Diese modulare Struktur von Db2 ist im man#Diag beschrieben
subsystem = A subordinate system that can operate independently or as a component of a larger system. For example, a DB2 subsystem is a complete, self-contained, stand-alone DB2 environment. However, using DDF, users in one subsystem can interface with other subsystems.
synchronousIO = Read or write operations that are executed under a thread’s TCB, causing application processing to wait until the I/O activity completes.
synonym = An alternative name that you can use in SQL statements to refer to a table or a view within the local subsystem. A table and its synonyms must exist within the same DB2 subsystem and are accessed by their creator only. When a table is dropped, the synonyms are also dropped. Synonyms are useful to program development.
Bei CS werden Synonyms nicht verwendet wegen der damit verbundenen sehr aufwendigen Administration.
Bei CS werden Synonyms nicht verwendet wegen der damit verbundenen sehr aufwendigen Administration.
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table = Tabelle, Abkürzung tb. A named database object in which data is structured in columns and rows.
TS = tablespace. A pageSet used to store the rows of one or more table. Es gibz vier Typen von Tablespaces: simpleTablspace, segmentedTablspace, partitionedTablespace und UTS.
thread
- A task or process is started by a main program and that runs parallel to this main program. Once the task completes, control is returned to the main program.
### In DB2, a control structure used to communicate with an application.
- A task or process is started by a main program and that runs parallel to this main program. Once the task completes, control is returned to the main program.
trigger = An event-driven procedure that is automatically executed when you insert, delete, or update data in a specified table. You can use triggers to update column values across different tables, and thereby help maintain the referential integrity of your database.
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unitOfRecovery = All the recovery information for an application plan. The unit of recovery begins with an URID, and ends with the next commit or with the termination of the application plan.
URID = Unit of recovery ID, which is the RBA for the first update, insert, or delete that a plan performs.
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view = A virtual table that consists of an SQL SELECT statement that accesses data from one or more tables and views. A view never stores data.
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