SQL/MX Glossary

Glossary

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Glossary-13

field

named CAT.SCH.MOD, when externally qualified with the table set tabset1, version

ver3, and group grp2, becomes CAT.SCH.GRP2^MOD^TABSET1^VER3. For more

information, see the SQL/MX Programming Manual for C and COBOL or the SQL/MX

Programming Manual for Java.

field. A portion of a record reserved for a specific item of information. In relational terms,

each column of a table represents one field. In a datetime or INTERVAL column value,

a datetime field or INTERVAL field, such as HOUR, is a specific part of the column.

file. The physical storage for a table, index, table partition, or index partition. The creation

of a table or index implicitly creates a file or files to contain the data, one file for each

partition. The names of the storage files are system-generated.

file attribute. An attribute that describes a physical characteristic of a file (containing tables,

indexes, or partitions) such as block size, record length, the number and sizes of

extents, or whether the file is audited. The file attributes potentially affect the

performance of applications that use the files.

file label. A label, containing file information in encoded form, associated with each table,

index, view, table partition, and index partition.

file organization. The physical file organization available for tables. See also entry-

sequenced file and key-sequenced file.

first key. The clustering-key value specified for the first row in a partition. Whether the value

in each key column is high or low depends on the ascending or descending collating

sequence defined for the column. The value is the lowest in the partition for ascending

columns and the highest for descending columns.

foreign key. An integrity constraint that requires each value in a column or set of columns

to match a value in a related table’s UNIQUE or PRIMARY KEY. FOREIGN KEY

integrity constraints also define referential integrity actions that dictate what SQL/MX

should do with dependent data if the data it references is altered. See also primary key

and integrity constraint.

function. A routine that returns a value. Contrast with procedure. See also built-in function

and routine.

generator. The last phase of the SQL compiler. This portion of the compile process takes

the optimal query plan and generates the executable query tree for the run-time

component.