- access method
- A set of server routines that the database server uses to
access and manipulate an index or a table. B-tree is the default
secondary access method used by DataBlade modules. Some DataBlade
modules have their own access methods, with routines defined by
the module.
See also primary access method, secondary access method.
- access privilege
- Permission for a user to perform an operation in a specific
database, table, table fragment, or column.
- ActiveX value object
- A Microsoft Common Object Model (COM)-compliant
object that contains a client-side copy of an opaque type and its
support routines.
See also value object.
-
aggregate function
- A function that performs a mathematical operation on a set
of rows selected by a query and returns a single value that contains information
about those rows. Aggregates use one or more support functions to
perform the aggregate operations. Examples of built-in aggregates
include SUM, AVG,
and COUNT.
- arithmetic function
- A function that returns a value by performing a mathematical
operation on one or more arguments.
- B-tree index
- A type of index that uses a balanced tree structure for efficient
record retrieval. B-tree indexes store key data in ascending or
descending order.
- BLOB
- A smart large object data type that stores any kind of binary
data, including images. The database server performs no interpretation
on the contents of a BLOB column.
See also smart large object.
-
built-in cast
- A cast that is built into the database server. A built-in
cast performs automatic conversions between different built-in data
types.
-
built-in data type
- A fundamental data type defined by the database server: for
example, INTEGER, CHAR,
or SERIAL8.
-
built-in function
- A predefined, SQL-invoked function
that provides some basic arithmetic and other operations, such as cos(), log(),
or today().
-
cast
- A mechanism that the database server uses to convert data
from one data type to another. The server provides built-in casts
that it performs automatically. Users can create both implicit and explicit
casts.
See also cast support function, explicit cast, implicit cast, built-in cast.
-
cast support function
- A function that is used to implement an implicit or explicit
cast by performing the necessary operations for conversion between
two data types. A cast support function is optional unless the internal
storage representations of the two data types are not equivalent.
- class
- A category of objects that have common properties and are
managed through a specific system table. Informix database classes
include access methods, aggregates, casts, routines, operators,
tables, and types.
- client files
- The files that reside on a client workstation that accesses
a DataBlade module's objects. Not all DataBlade modules
have client files. Examples include client applications or client libraries
that are specific to the DataBlade module.
- CLOB
- A smart large object data type that stores blocks of text
items, such as ASCII or PostScript files.
See also smart large object.
- collection
- An instance of a collection data type; a group of elements
of the same data type stored in a SET, MULTISET,
or LIST type constructor.
See also collection data type.
-
collection data type
- A complex data type that groups values, called elements, of
a single data type in a column. Collection data types consist of the SET, MULTISET,
or LIST type constructor and an element
type, which can be any data type, including a complex data type.
-
commutator function
- A Boolean function that accepts the same two arguments, in
reverse order, as another Boolean function, and returns the same result.
The query optimizer might choose the commutator function if it executes
more quickly in a given query than the specified function.
See also negator function.
- complex data type
- A data type that is built from a combination of other data
types using an SQL type constructor or
the CREATE ROW TYPE statement, and whose
components can be accessed through SQL statements.
Complex data types include collection data types and row data types.
- concurrency
- The ability of two or more processes to access the same database
simultaneously.
- constructed data type
- A complex data type created with a type constructor: for example,
a collection data type or an unnamed row data type.
- constructor
- See type constructor.
- data file
- A flat file containing data to be loaded into the database.
- data type
- See built-in data type, extended data type.
-
database object
- A discrete entity within a database, such as a data type,
a routine, a table, an index, or a view. Users can define database
objects with the CREATE statement.
- DataBlade API
- The C application programming interface (API)
for your Informix database server. The DataBlade API is
used for the development of DataBlade modules. The DataBlade API contains routines
to process data in the database server and return the results to
the calling application.
- DataBlade module
- A group of database objects and supporting code that extends
an object-relational database to manage new kinds of data or add
new features. A DataBlade module can include new data types, routines,
casts, access methods, SQL code, client
code, and installation programs.
- distinct data type
- A data type based on an existing opaque, built-in, distinct,
or named row data type, which is known as its source type. The distinct
data type has the same internal storage representation as its source
type, but it has a different name. To compare a distinct data type with
its source type requires an explicit cast. A distinct data type
inherits all routines that are defined on its source type.
- element
- A member of a collection. See also collection data type.
- element data type
- The data type of the elements in a collection.
-
explicit cast
- A cast that requires a user to specify the CAST AS keyword
or cast operator ( :: ) to convert data from one data type to another.
See also cast, cast support function.
-
extended data type
- A data type that is not built-in: namely, a collection data
type, row data type, opaque data type, or distinct data type.
- external function
- An external routine that can accept one or more arguments
and returns a single value.
-
external procedure
- An external routine that can accept one or more arguments,
but does not return a value.
- external routine
- A routine written in a language external to the database (for
example, C), whose body is stored outside
the database but whose name and parameters are registered in the
system catalog tables.
- field
- A component of a named row data type. A field has a name and
a data type and is accessed in an SQL statement
by using dot notation: for example, row_type_name.field_name.
-
function
- A routine that can accept arguments and returns one or more
values.
See also built-in function, routine, user-defined function.
- functional index
- An index that stores the result of executing a specified function
on a table column.
- function overloading
- See routine overloading.
-
Global Language Support
(GLS)
- An application environment that allows IBM Informix application-programming
interfaces (APIs) and database servers
to handle different languages, cultural conventions, and code sets.
Developers use the GLS libraries to manage
all string, currency, date, and time data types in their code. Using GLS,
you can add support for a new language, character set, and encoding
by editing resource files, without access to the original source code
and without rebuilding the DataBlade module or client software.
- grant privileges
- Privileges granted to one or more users. The users then have
the authority to grant these same privileges to other users. A privilege list
identifies the exact privileges to be granted.
- hash rule
- A user-defined algorithm that maps each row in a table to
a set of hash values used to determine the fragment in which a row
is stored.
-
implicit cast
- A cast that the database server automatically performs to
convert data from one data type to another.
See also cast, cast support function.
-
index
- A structure of pointers to rows of data in a table. An index
optimizes the performance of database queries by ordering rows to
make access faster.
-
Informix user ID
- A login user ID (login user name)
that must be valid on all computer systems (operating systems) involved
in the client's database access. Often referred to as the
client's "user ID" or "user
name."
-
Informix user password
- A user ID password that must be valid
on all computer systems (operating systems) involved in the client's
database access. When the client specifies an explicit user ID,
most computer systems require the Informix user password to validate
the user ID.
- INFORMIXDIR
- The Informix environment variable that specifies the directory
in which IBM Informix products are installed.
- inheritance
- The property that allows a named row data type or a typed
table to inherit representation (data fields and columns) and behavior
(routines, operators, and rules) from a named row data type or typed
table superior to it in a defined hierarchy. Inheritance allows
for incremental modification, so that an object can inherit a general
set of properties and then add properties that are specific to itself.
Under certain circumstances, distinct data types can also have inheritance.
- input parameter
- A placeholder within a prepared SQL statement that represents
a value to be provided at the time the statement is executed.
- interface
- In the DataBlade Developers Kit, a way to refer to a DataBlade
module within another DataBlade module. Because an interface creates
a dependency on another module, BladeManager ensures that the originating
module is registered before the module that contains the interface.
- iterator function
- A function that returns a set of results one row at a time.
The database server calls iterator functions repeatedly to process
all the return values.
- keyword
- A word that has meaning to a programming language. In Informix SQL, keywords
are shown in syntax diagrams in all uppercase letters. They must
be used in SQL statements exactly as shown
in the syntax, but they can be entered as either uppercase or lowercase letters.
- large object
- A data object that exceeds 255 bytes in length. A large object
is logically stored in a table column but physically stored independently of
the column, because of its size. Large objects can contain non-ASCII data.
Your Informix database server recognizes two kinds of large objects:
simple large objects (TEXT, BYTE)
and smart large objects (CLOB, BLOB).
See also SLV, smart large object.
-
LIST constructor
- A type constructor used to create a LIST data
type.
- LIST data type
- A collection data type in which elements are ordered and duplicates
are allowed.
See also collection data type.
- locale
- A set of files that define the native-language behavior of
the program at runtime. The rules are usually based on the linguistic
customs of the region or the territory. The locale can be set through
an environment variable that dictates output formats for numbers,
currency symbols, dates, and time, as well as collation order for character
strings and regular expressions.
See also Global Language Support (GLS).
- LVARCHAR
- A built-in data type that stores varying-length character
data greater than 256 bytes. It is used for input and output casts
for opaque data types. LVARCHAR supports
code-set order for comparisons of character data.
- math function
- See built-in function, operator function.
- member
- A component of an opaque data type. A member has a name and
a data type and can be accessed in an SQL statement
by user-defined accessor functions.
- multirepresentational data type
- A data type whose storage location can switch between a row and
a smart large object.
-
MULTISET constructor
- A type constructor used to create a MULTISET data
type.
- MULTISET data type
- A collection data type in which elements are not ordered and
duplicates are allowed.
See also collection data type.
-
named row data type
- A row data type that is created with the CREATE ROW TYPE statement and
has a name. A named row data type can be used to construct a typed
table and can be part of a type or table hierarchy.
See also row data type, unnamed row data type.
-
negator function
- A Boolean function that accepts the same arguments in the
same order as another Boolean function, but returns the Boolean complement.
The query optimizer might choose the negator function if it executes
more quickly in a given query than the specified function.
See also commutator function.
- nonvariant function
- A function that always returns the same value when passed
the same arguments.
-
not null constraint
- A constraint on a column that specifies that the column cannot
contain null values.
- object
- See database object.
- objects script
- A file containing SQL statements that
describe the objects in a DataBlade module.
- opaque data type
- An extended data type that contains one or more members but
whose internal structure is interpreted by the database server using
user-defined support routines.
- operator
- A symbol, such as =, >, +, or -, that invokes an
operator function.
- operator binding
- The association between an operator and an operator function.
Operator binding occurs when an SQL statement contains an operator
and the database server automatically invokes the associated operator
function.
-
operator class
- The set of operators that the database server associates with
a secondary access method. When an index is created, it is associated with
a particular operator class.
-
operator function
- An arithmetic function that has a corresponding operator symbol.
An operator function processes one to three arguments and returns
a value. For example, the plus() function corresponds
to the "+" operator symbol.
- overloading
- See routine overloading.
-
parallel database query
(PDQ)
- A query that allows the database server to distribute the execution
of the query among several virtual processors by dividing it into
subqueries.
- parallelizable routine
- A routine that can be executed within a parallel database
query statement.
See also parallel database query (PDQ).
- parameter
- A variable to which a value can be assigned in a specific
application. In a routine, a parameter is the placeholder for the
argument values passed to the subroutine at runtime.
- polymorphism
- See routine overloading.
- prepare script
- A file containing SQL statements that describe the DataBlade
module. There are two types of prepare scripts:
- The script called prepare.sql contains information
about the module that is not language-specific.
- Scripts with names in the format prepare.locale.sql contain
language-specific information such as the module and vendor descriptions.
-
primary access method
- A set of routines that perform table operations such as inserting, deleting,
updating, and scanning data. The database server provides a virtual
table interface (VTI), with which advanced
users can create primary access methods for virtual tables.
- privilege
- Rights granted to specific users on specific objects within
the database. A privilege list identifies the exact privileges that
are applicable for a particular object and that are held by the
user invoking the grant. Privileges are granted or revoked on a
database object using the GRANT and REVOKE statements.
-
procedure
- A routine that can accept arguments but does not return a
value.
See also external procedure, stored procedure.
- procedure overloading
- See routine overloading.
- query optimizer
- A server facility that estimates the most efficient plan for
executing a query in the DBMS. The optimizer
considers the CPU cost and the I/O cost
of executing a plan.
- R-tree index
- A type of index that uses a tree structure based on overlapping
bounding rectangles to speed access to spatial and multidimensional
data types.
- registration
- The process of executing SQL statements
to create DataBlade module objects or individual user-defined routines
in a database and giving the database server the location of the associated
shared object file. Registration makes a DataBlade module available
for use by client applications that open that database.
-
routine
- A named collection of program statements that perform a particular
task and can accept arguments. Routines include functions, which
return one or more values, and procedures, which do not return values.
See also function, procedure, user-defined routine.
- routine resolution
- The process that the database server uses to determine which
routine to execute, given the routine signature.
See also routine signature.
-
routine signature
- The information that the database server uses to identify
a routine. The signature of a routine includes the type of the routine
(function or procedure), the routine name, the number of parameters,
the data types of the parameters, and the order of the parameters.
In an ANSI-compliant database, the name
of the routine is specified as owner.name.
-
routine overloading
- Defining more than one routine with the same name but different parameter
lists.
-
ROW constructor
- The type constructor used to construct unnamed row data types.
-
row data type
- A complex data type consisting of a group of ordered data
elements (fields) of the same or different data types. The fields
of a row type can be of any supported built-in or extended data
type, including complex data types, except SERIAL and SERIAL8 and,
in certain situations, TEXT and BYTE.
There are two kinds of row data types:
- Named row types, created using the CREATE ROW TYPE statement
- Unnamed row types, created using the ROW constructor
See also named row data type, unnamed row data type.
-
sbspace
- A logical storage area that contains one or more chunks that
store only smart large object data.
-
secondary access method
- A set of database server functions that build, access, and
manipulate an index structure: for example, a B-tree, an R-tree,
or an index structure provided by a DataBlade module. Typically,
a secondary access method speeds up the retrieval of data.
When an SQL query uses an index created
on a secondary access method, it accesses the index using the functions
defined in the operator class associated with that access method.
See also operator class.
- selectivity function
- A function that calculates the percentage of rows that will
be returned by a filter function in the WHERE clause
of a query. The optimizer uses selectivity information to determine the
fastest way to execute an SQL query.
-
SET constructor
- A type constructor used to create a SET data
type.
- SET data type
- A collection data type in which elements are not ordered and
duplicates are not allowed.
See also collection data type.
- shared memory
- A portion of main memory that processes can use to communicate
and share common data, thus reducing disk I/O and improving
performance.
- signature
- See routine signature.
-
SLV
- Abbreviation for statement local variable.
-
smart large object
- A large object that:
- is stored in an sbspace, a logical storage area that contains
one or more chunks.
- has read, write, and seek properties similar to a UNIX file.
- is recoverable.
- obeys transaction isolation modes.
- can be retrieved in segments by an application.
Smart large objects include CLOB and BLOB data types.
- SPL
- Abbreviation for Stored Procedure Language.
- statement local variable (SLV)
- A variable for storing a value that a function returns indirectly, through
a pointer, in addition to the value that the function returns directly.
An SLV's scope is limited to the
statement in which it is used. The RANK parameter
of the Resembles operator function is an SLV.
-
stored procedure
- A user-defined routine that is stored in a database in executable
format. Stored procedures are used to execute frequently repeated tasks,
to improve performance, and to monitor access to data. Stored procedures
are written in Stored Procedure Language (SPL).
-
Stored Procedure Language
- An Informix extension to SQL that
provides flow-control features such as sequencing, branching, and looping,
comparable to those features provided in the SQL/PSM standard. SPL can
be used for writing DataBlade module routines.
- strategy functions
- The functions that the optimizer uses to determine what filters
in a query can use a secondary access method (index).
- subquery
- A SELECT statement within a WHERE clause.
-
support routines
- The internal routines that the database server automatically
invokes to process a data type, cast, aggregate, or access method.
The database server uses user-defined support routines to perform
operations on opaque data types (such as converting to and from
the internal, external, and binary representations of the type).
An secondary access method uses a support routine in an operator
class to perform operations on an index (such as building or searching).
- system catalog
- A group of database tables that contain information about
the database itself, such as the names of tables or columns in the
database, the number of rows in a table, the information about indexes
and database privileges, and so on.
- table
- A rectangular array of data in which each row describes a
single entity and each column contains the values for each category
of description. A table is sometimes referred to as a base table to
distinguish it from the views, indexes, and other objects defined
on the underlying table or associated with it.
-
type constructor
- An SQL keyword that indicates to
the database server the type of complex data to create.
See also LIST constructor, MULTISET constructor, ROW constructor, SET constructor.
- type inheritance
- The property that allows a named row data type to inherit
representation (data fields, columns) and behavior (routines, operators,
rules) from a named row type above it in the type hierarchy.
-
unnamed row data type
- A row type created with the ROW constructor
that has no defined name and no inheritance properties. Two unnamed
row types are equivalent if they have the same number of fields
and if corresponding fields have the same data type, even if the
fields have different names.
- unregistration
- The process of executing SQL statements
to drop DataBlade module objects or individual user-defined routines
in a database and removing the ability to access the associated shared
object file from the database server.
-
user-defined function
- A user-defined routine that returns a value.
-
user-defined routine
- A routine, written in one of the languages that your Informix
database server supports, that provides added functionality for data
types or encapsulates application logic.
- user-defined procedure
- A user-defined routine that does not return a value.
-
user-defined statistics
- Information about the opaque data type values in your database
that is collected by the UPDATE STATISTICS statement, which
calls user-defined functions to calculate the statistics. The optimizer
uses these statistics to determine the fastest way to execute an SQL query.
-
user-defined virtual processor
- (1) A virtual processor that executes the user-defined routines that
are assigned to it.
- (2) See also virtual processor.
-
value object
- A self-contained binary object that provides standard interfaces
to its callers. Value objects can be used in client applications.
- variant function
- A function that, with the same arguments, can either return
different values or have varying side effects, such as updating
a table or external file.
-
virtual processor
- One of the multithreaded processes that make up the database
server and are similar to the hardware processors in the computer.