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add [an ODBC data source]
Make a data source available to ODBC through the Add operation of the ODBC Administrator utility. Adding a data source tells ODBC where a specific database resides and which ODBC driver to use to access it. Adding a data source also invokes a setup dialog box for the particular driver so you can provide other details the driver needs to connect to the database.
ADMIN
The default owner name for all system tables in a FairCom DB SQL database. Users must qualify references to system tables as ADMIN.tablename.
alias
A temporary name for a table or column specified in the FROM clause of an SQL query expression. Also called correlation name. Derived tables and search conditions that join a table with itself must specify an alias. Once a query specifies an alias, references to the table or column must use the alias and not the underlying table or column name.
applet
A special kind of Java program whose compiled class files a Java-enabled browser can download from the Internet and run.
ASCII
(American Standard Code for Information Interchange) A 7-bit character set that provides 128 character combinations.
bytecode
Machine-independent code generated by the Java compiler and executed by the Java interpreter.
candidate key
Another term for unique key.
cardinality
Number of rows in a result table.
Cartesian product
Also called cross-product. In a query expression, the result table generated when a FROM clause lists more than one table but specifies no join conditions. In such a case, the result table is formed by concatenating every row of every table with all other rows in all tables. Typically, Cartesian products are not useful and are slow to process.
client
Generally, in client/server systems, the part of the system that sends requests to servers and processes the results of those requests.
collation
The rules used to control how character strings in a character set compare with each other. Each character set specifies a collating sequence that defines relative values of each character for comparing, merging and sorting character strings.
column alias
An alias specified for a column. See alias.
constraint
Part of an SQL table definition that restricts the values that can be stored in a table. When you insert, delete, or update column values, the constraint checks the new values against the conditions specified by the constraint. If the value violates the constraint, it generates an error. Along with triggers, constraints enforce referential integrity by insuring that a value stored in the foreign key of a table must either be null or be equal to some value in the matching unique or primary key of another table.
correlation name
Another term for alias.
cross product
Another term for Cartesian product.
data dictionary
Another term for system catalog.
data source
See ODBC data source.
derived table
A virtual table specified as a query expression in the FROM clause of another query expression.
driver manager
See JDBC driver manager and ODBC driver manager.
foreign key
A column or columns in a table whose values must either be null or equal to some value in a corresponding column (called the primary key) in another table. Use the REFERENCES clause in the SQL CREATE TABLE statement to create foreign keys.
form of use
The storage format for characters in a character set. Some character sets, such as ASCII, require one byte (octet) for each character. Others, such as Unicode, use two bytes, and are called multi-octet character sets.
input parameter
In a stored procedure specification, an argument that an application must pass when it calls the stored procedure. In an SQL statement, a parameter marker in the statement string that acts as a placeholder for a value that will be substituted when the statement executes.
interface
In Java, a definition of a set of methods that one or more objects will implement. Interfaces declare only methods and constants, not variables. Interfaces provide multiple-inheritance capabilities.
Java snippet
See snippet.
JDBC
Java Database Connectivity: a part of the Java language that allows applications to embed standard SQL statements and access any database that implements a JDBC driver.
JDBC driver
Database-specific software that receives calls from the JDBC driver manager, translates them into a form that the database can process, and returns data to the application.
JDBC driver manager
A Java class that implements methods to route calls from a JDBC application to the appropriate JDBC driver for a particular JDBC URL.
join
A relational operation that combines data from two tables.
main-memory storage system / storage manager
A storage system and storage manager supplied with c-treeSQL. It provides a mechanism for implementations to store data in memory instead of on disk. By using the main-memory storage system for volatile data such as temporary sort tables and dynamic indexes, implementations can improve performance of many queries, such as joins.
manager
A main component of the SQL engine. The SQL engine includes several managers, including the SQL statement manager, parser, and optimizer.
metadata
Data that details the structure of tables and indexes in the c-tree Plus. The SQL engine stores metadata in the system catalog.
octet
A group of eight bits. Synonymous with byte, and often used in descriptions of character-set encoding format.
ODBC application
Any program that calls ODBC functions and uses them to issue SQL statements. Many vendors have added ODBC capabilities to their existing Windows-based tools.
ODBC data source
In ODBC terminology, a specific combination of a database system, the operating system it uses, and any network software required to access it. Before applications can access a database through ODBC, you use the ODBC Administrator to add a data source -- register information about the database and an ODBC driver that can connect to it -- for that database. More than one data source name can refer to the same database, and deleting a data source does not delete the associated database.
ODBC driver
Vendor-supplied software that processes ODBC function calls for a specific data source. The driver connects to the data source, translates the standard SQL statements into syntax the data source can process, and returns data to the application. c-treeSQL includes an ODBC driver that provides access to the c-treeSQL Server.
ODBC driver manager
A Microsoft-supplied program that routes calls from an application to the appropriate ODBC driver for a data source.
optimizer
Within the SQL engine, the manager that analyzes costs and statistics associated with the statement and converts the relational algebra tree to the most efficient form for execution. The optimizer stores the trees for later use.
output parameter
In a stored procedure specification, an argument in which the stored procedure returns a value after it executes.
package
A group of related Java classes and interfaces, like a class library in C++. The Java development environment includes many packages of classes that procedures can import. The Java runtime system automatically imports the java.lang package. Stored procedures must explicitly import other classes by specifying them in the IMPORT clause of a CREATE PROCEDURE statement.
parameter marker
A question mark (?) in a procedure call or SQL statement string that acts as a placeholder for an input or output parameter supplied at runtime when the procedure executes. The CALL statement (or corresponding ODBC or JDBC escape clause) use parameter markers to pass parameters to stored procedures, and the SQLIStatement, SQLPStatement, and SQLCursor objects use them within procedures.
primary key
A subset of the fields in a table, characterized by the constraint that no two records in a table may have the same primary key value, and that no fields of the primary key may have a null value. Primary keys are specified in a CREATE TABLE statement.
procedure body
In a stored procedure, the Java code between the BEGIN and END keywords of a CREATE PROCEDURE statement.
procedure result set
In a stored procedure, a set of data rows returned to the calling application. The number and data types of columns in the procedure result set are specified in the RESULT clause of the CREATE PROCEDURE statement. The procedure can transfer data from an SQL result set to the procedure result set or it can store data generated internally. A stored procedure can have only one procedure result set.
procedure specification
In a CREATE PROCEDURE statement, the clauses preceding the procedure body that specify the procedure name, any input and output parameters, any result set columns, and any Java packages to import.
procedure variable
A Java variable declared within the body of a stored procedure, as compared to a procedure input parameter or output parameter, which are declared outside the procedure body and are visible to the application that calls the stored procedure.
query expression
The fundamental element in SQL syntax. Query expressions specify a result table derived from some combination of rows from the tables or views identified in the FROM clause of the expression. Query expressions are the basis of SELECT, CREATE VIEW, and INSERT statements, and can be used in some expressions and search conditions.
referential integrity
The condition where the value stored in a database table’s foreign key must either be null or be equal to some value in another table’s the matching unique or primary key. SQL provides two mechanisms to enforce referential integrity: constraints specified as part of CREATE TABLE statements prevent updates that violate referential integrity, and triggers specified in CREATE TRIGGER statements execute a stored procedure to enforce referential integrity.
repertoire
The set of characters allowed in a character set.
result set
In a stored procedure, either an SQL result set or a procedure result set. More generally, another term for result table.
result table
A virtual table of values derived from columns and rows of one or more tables that meet conditions specified by an SQL query expression.
row identifier
Another term for tuple identifier.
search condition
The SQL syntax element that specifies a condition that is true or false about a given row or group of rows. Query expressions and UPDATE statements can specify a search condition. The search condition restricts the number of rows in the result table for the query expression or UPDATE statement. Search conditions contain one or more predicates. Search conditions follow the WHERE or HAVING keywords in SQL statements.
selectivity
The fraction of a table’s rows returned by a query.
server
Generally, in client/server systems, the part of the system that receives requests from clients and responds with results to those requests.
snippet
In a stored procedure, the sequence of Java statements between the BEGIN and END keywords in the CREATE PROCEDURE (or CREATE TRIGGER) statement. The Java statements become a method in a class the SQL engine creates and submits to the Java compiler.
SQL diagnostics area
A data structure that contains information about the execution status (success, error or warning conditions) of the most recent SQL statement. The SQL-92 standard specified the diagnostics area as a standardized alternative to widely varying implementations of the SQLCA. c-treeSQL supports both the SQLCA and the SQL diagnostics area. The SQL GET DIAGNOSTICS statement returns information about the diagnostics area to an application, including the value of the SQLSTATE status parameter.
SQL engine
The core component of the FairCom DB SQL environment. The SQL engine receives requests from applications, processes them, and returns results. The SQL engine conveys requests to the c-tree Plus engine.
SQLCA
SQL Communications area: A data structure that contains information about the execution status (success, error or warning conditions) of the most recent SQL statement. The SQLCA includes an SQLCODE field. The SQLCA provides the same information as the SQL diagnostics area, but is not compliant with the SQL-92 standard. c-treeSQL supports both the SQLCA and the SQL diagnostics area.
SQLCODE
An integer status parameter whose value indicates the condition status returned by the most recent SQL statement. An SQLCODE value of zero means success, a positive value means warning, and a negative value means an error status. SQLCODE is superseded by SQLSTATE in the SQL-92 standard. Applications declare either SQLSTATE or SQLCODE, or both. SQL returns the status to SQLSTATE or SQLCODE after execution of each SQL statement.
SQL result set
In a stored procedure, the set of data rows generated by an SQL statement (SELECT and, in some cases, CALL).
SQLSTATE
A 5-character status parameter whose value indicates the condition status returned by the most recent SQL statement. SQLSTATE is specified by the SQL-92 standard as a replacement for the SQLCODE status parameter (which was part of SQL-89). SQLSTATE defines many more specific error conditions than SQLCODE, which allows applications to implement more portable error handling. Applications declare either SQLSTATE or SQLCODE, or both. SQL returns the status to SQLSTATE or SQLCODE after execution of each SQL statement.
stored procedure
A snippet of Java source code embedded in an SQL CREATE PROCEDURE statement. The source code can use all standard Java features as well as use c-treeSQL-supplied Java classes for processing any number of SQL statements.
system catalog
Tables created by the SQL engine that store information about tables, columns, and indexes that make up the database. The SQL engine creates and manages the system catalog.
system tables
Another term for system catalog.
tid
Another term for tuple identifier.
transaction
A group of operations whose changes can be made permanent or undone only as a unit to protect against data corruption.
trigger
A special type of stored procedure that helps insure referential integrity for a database. Like stored procedures, triggers also contain Java source code (embedded in a CREATE TRIGGER statement) and use c-treeSQL Java classes. However, triggers are automatically invoked (“fired”) by certain SQL operations (an insert, update, or delete operation) on the trigger’s target table.
trigger action time
The BEFORE or AFTER keywords in a CREATE TRIGGER statement. The trigger action time specifies whether the actions implemented by the trigger execute before or after the triggering INSERT, UPDATE, or DELETE statement.
trigger event
The statement that causes a trigger to execute. Trigger events can be SQL INSERT, UPDATE, or DELETE statements that affect the table for which a trigger is defined.
triggered action
The Java code within the BEGIN END clause of a CREATE TRIGGER statement. The code implements actions to be completed when a triggering statement specifies the target table.
tuple identifier
A unique identifier for a tuple (row) in a table. The SQL scalar function ROWID and related functions return tuple identifiers to applications.
Unicode
A superset of the ASCII character set that uses two bytes for each character rather than ASCII's 7-bit representation. Able to handle 65,536 character combinations instead of ASCII's 128, Unicode includes alphabets for many of the world's languages. The first 128 codes of Unicode are identical to ASCII, with a second-byte value of zero.
unique key
A column or columns in a table whose value (or combination of values) must be unique. Use the UNIQUE clause of the SQL CREATE TABLE statement to create unique keys. Unique keys are also called candidate keys.
URL
In general, a Universal Resource Locater used to specify protocols and locations of items on the Internet. In JDBC, a database connection string in the form jdbc:subprotocol:subname. The c-treeSQL JDBC Driver format for database URLs is jdbc:ctree://<host>[:portnumber]/<dbname>[?param=value[¶m=value]...], as explained in JDBC Connection String.
view
A virtual table that recreates the result table specified by a SELECT statement. No data is stored in a view, but other queries can refer to it as if it were a table containing data corresponding to the result table it specifies.
virtual table
A table of values that is not physically stored in a database, but instead derived from columns and rows of other tables. SQL generates virtual tables in its processing of query expressions: the FROM, WHERE, GROUP BY and HAVING clauses each generate a virtual table based on their input.
virtual machine
The Java specification for a hardware-independent and portable language environment. Java language compilers generate code that can execute on a virtual machine. Implementations of the Java virtual machine for specific hardware and software platforms allow the same compiled code to execute without modification.
