Advanced program-to-program communication (APPC) allows transaction programs on one system to communicate with transaction programs located on other systems in a Systems Network Architecture (SNA) network.
Authorizations and authorization names for users and groups
A person who is authorized to use a specific database or specific objects in it is called a DB (database) user (or user, for short). You can provide authorization in two ways. You provide it explicitly by granting it directly to the person. You provide it implicitly by granting it directly to an aggregation of persons (called a DB group or group) to which the person belongs. All users belong to a default group called PUBLIC. If you want to define additional groups, you must use the underlying operating system to do so.
This overview covers:
Types of authorization
There are two types of authorization--privileges and authorities. A privilege is the right to access a specific database object in a specific way. For example, the UPDATE privilege on a table is the right to change an entry in the table. An authority is the right to exercise multiple privileges, or perform operations, or both, on a database or its objects. For example, DBADM authority includes the right to exercise all privileges on a database's objects and to perform such operations as creating event monitors and reorganizing tables. For more about authorizations, see "Controlling Database Access" in the Administration Guide and the sections on GRANT statements in the SQL Reference.
The Grant option
When you grant a privilege on an object to a user or group, you can also give the user or group the right to grant the same to other users and groups. This right is called the Grant option. (Exception: the CONTROL privilege doesn't have this option; however, a user with SYSADM or DBADM authority can grant the CONTROL privilege to others.) With the Grant option, a user can grant a privilege on an object to other users and to groups. When a group holds a privilege, with the Grant option, on an object, each member of the group can grant that same privilege on the same object to other groups and users.
For example, suppose you want GROUP1's members to change values of specified columns in rows of TABLE1 and to allow other users to do the same. To achieve this, you could grant GROUP1 the UPDATE privilege, with the Grant option, on TABLE1. Each member of GROUP1 could then grant the UPDATE privilege on TABLE1 to other groups and to individual users.
Authorization names
An authorization name is an identifier that is used in various SQL statements. In an SQL statement for granting or revoking an authorization, an authorization name is an identifier for the user or group that is receiving or relinquishing the authorization. DB2 obtains each user's and group's authorization name from the underlying operating system.
An area of storage where the data from the tables in a database is cached in memory.
In DB2 Universal Database Extended Enterprise Edition a connection partition is the connection that is made to a database partition by an application. A connection partition is established at each database partition that contains data that will be used by the application.
Cyclical referential constraint
A cyclical referential constraint occurs when tables are dependent on (or descendents of) one another. For example, if table T1 has a foreign key that is related to T2's primary key, and T2 has a foreign key that is related to T1's primary key, then they are dependent on one another.
A relational database presents data as a collection of tables (each table consisting of data logically arranged in columns and rows).
In addition to data, each database includes a set of system catalog tables, which describe the logical and physical structure of the data; a configuration file, which contains the parameter values associated with the database; and a recovery log, which logs ongoing transactions and transactions that can be archived.
In DB2, a unique database name must be specified when a database is created.
In a partitioned database environment, the database is made up of different
database partitions.
A database alias is an alternative name used to identify a database. A database is referred to by the alias specified for that database in the system database directory.
A database alias must be unique within the system database directory. Therefore, to connect to databases with the same name located in different directory paths, you must specify a unique alias when cataloging the databases. When a database is created, it is cataloged with an alias equal to the database name.
Database aliases of a database alias are not supported.
A database alias consists of 1 to 8 characters from the following set of characters:
Also, an alias:
Database connection services directory
A database connection services (DCS) directory contains entries for DRDA and the corresponding application requester that can be used to access them.
The DCS directory is located in the path where the database manager is installed. A database must have corresponding entries in the system database directory and the node directory before it can be accessed successfully.
Delimited ASCII format (DEL) is a file format used to import or load data. A DEL file is a sequential ASCII file. Rows in the file are separated by line feed sequences. Within a row, the individual cell values are separated by column delimiters.
An example of a DEL file is:
"Smith, Bob",4973,15.46 "Jones, Suzanne",12345,16.34 "Williams, Sam",452123,193.78
The character strings are delimited by quotation marks; each column is delimited within the row by commas.
This file format is commonly used to exchange data with a variety of products using different column delimiters.
A distinct type is a user-defined data type that shares its internal representation with an existing type (its source type), but is considered to be a separate type for most operations. For example, you can define a distinct type called PICTURE and base it on the existing BLOB data type. Then, you can create tables with columns that use the PICTURE data type.
Distributed Relational Database Architecture (DRDA)
Distributed Relational Database Architecture (DRDA) is an architecture that defines formats and protocols for providing transparent access to remote data. DRDA defines two types of functions -- the application requester function and the application server function.
For example, you can use the DB2 Client Application Enabler (CAE) as the application requester that provides access to DB2 for MVS/ESA application servers.
Integrated Exchange Format (IXF)
The Integrated Exchange Format (IXF) data interchange architecture is a host file format designed to enable exchange of relational database structure and data. The personal computer (PC) version of the IXF format (PC/IXF) is a database manager adaptation of the host IXF format.
A PC/IXF file contains a structured description of a database table or view. Data that was exported in PC/IXF format can be imported or loaded into another DB2 database.
Internetwork Packet Exchange (IPX) is a communications protocol used in a NetWare LAN environment to transfer data to a remote node. The Sequenced Packet Exchange (SPX), when built on top of IPX, guarantees the delivery of data packets.
Network Basic Input/Output System (NetBIOS) provides a programming interface to the local area network (LAN) so that an application program can have LAN communication without knowledge of and responsibility for some of the lower layer protocol functions.
Nondelimited ASCII format (ASC)
Nondelimited ASCII format (ASCII) is a file format used to import or load data. An ASC data file is a stream of ASCII characters consisting of data values organized by row and column. Rows in the data stream are separated by line feed sequences. Each column within a row is defined by beginning and ending byte positions. The data type of a given column in the ASC file is determined by the type of the target column in the database table or view.
An example of an ASC file is:
3 4 5 0.........0.........0.... Smith,B. 4973 15.46 Jones,S. 12345 16.34 Davis,S. 452121 93.78
The first column begins in position 30, the second column begins in position 42, and the third column begins in position 50.
This file format can be used for data exchange with applications, including word processors, that create flat text files with aligned column data.
A protocol is a set of rules that must be followed in a communication system.
DB2 supports the following protocols:
A block of procedural constructs and embedded SQL statements that is stored in a database and can be called by name. Stored procedures allow an application program to be run in two parts. One part runs on the client and the other on the server. This allows one call to produce several accesses to the database.
Transmission Control Protocol/Internet Protocol (TCP/IP) is a protocol (or set of rules and formats required to exchange data) that enables workstations to communicate with each other.
TCP/IP support is widely available to most of the workstation platforms, either as part of the operating system or as a separate product.
There are two pieces of information required when making a TCP/IP connection:
This file format is used to exchange data with WSF files that are generated or supported by:
Each WSF file represents one work sheet. The database manager uses the following conventions to interpret work sheets and to provide consistency in work sheets generated by its export operations:
A row of all nulls will be neither imported nor exported.
Some data may be lost when a table or view is imported into a file with WSF format.