CQL ( 1 ) USER COMMANDSCQL ( 1 )


NAME

cql - C query language

SYNOPSIS

cql [ options ] [ data ]

DESCRIPTION

cql applies C style expressions to flat database files. It fills the gap between awk(1) and full blown relational database management programs. A flat database is a sequence of newline terminated records of delimiter separated fields.

Files are processed as follows. cql first evaluates the begin expression if defined, then sequentially applies the select expression to all records. The action expression is evaluated for each record that select evaluates to non-0. After all records have been checked the done expression is evaluated if defined, and cql exits. The default select expression is 1 (all records are selected) and the default action expression prints the record on the standard output.

Depending on the input file declarations, cql may generate index files for quick record access. Indexes are used to filter out records for which select would evaluate to 0. Index files are placed in the current directory and each is named by changing the suffix to .hix or by adding a .hix suffix.

OPTIONS

-a, --active

Run in active mode by reading declarations and expressions from the standard input. The special sequence %% separates the declarations from the expressions. %% after an expression applies that expression to the input files. EOF terminates the active session. Active mode error message lines are prefixed with %% cql:.
-c, --compile=file

If file matches *.c then the cql expression are converted to C and placed in file, and cql exits. file may then be compiled with cc(1). Otherwise file is assumed to be a dll (compiled and linked from a .c file previously generated by clq) and is loaded into the current process.
-e|d, --expression=expr

expression defines the database schemas and the labelled expressions that control database traversal. Multiple --expression expressions are parsed in order from left to right.
-f, --file=file

Equivalent to -e "#include 'file'".
-l, --local

By default index files are only generated in the directory containing the data files; --local causes index files to be generated in the current directory.
-n, --index

Enable index file generation. If index files must be (re)generated and --noindex is on then cql exits with a diagnostic. On by default; -n means --noindex.
-r, --replace

Replace the top level database view with an updated view if there were updates.
-R, --regenerate

If index files are required then --regenerate forces them to be regenerated even if the otherwise seem up-to-date.
-u, --update

Only output updated records. By default all selected records are output.
-w, --warn

Disable malformed data warning messages. With --nowarn malformed records are silently repaired or discarded. On by default; -w means --nowarn.
-I, --include=dir

Add dir to the list of directories searched for include and library files. The default ../lib/cql directories on $PATH are added to this list.
-D, --debug=level

Set the debug trace level to level. Higher levels produce more output.
-T, --test=mask

Inclusive-or mask into the implementation defined test mask. Occasionally a particular mask may be used as a temporary bug workaround. Otherwise use at your own risk.
-g, --g2

(obsolete) Enable g2 output mode.

SCHEMAS

A schema is similar to a C struct declaration with the struct keyword omitted. A schema specifies names and types for the fields in a database record. The types are:
char*

A null-terminated C string.
date_t

A C unsigned long variable whose string representation is a date.
elapsed_t

A C long variable whose string representation is elapsed time in 1/100 seconds.
float

A C double variable.
hex
A C unsigned long variable whose string representation is hexadecimal.
int
A C long variable.
string

Equivalent to a null-terminated C char*.
unsigned

A C unsigned long variable.

Schemas are themselves types. schema field; declares a subfield within a record and schema* field; declares a field that indexes another schema. In this case the field value is a string key that is used to match the first field in the referenced schema. The register prefix denotes fields that should be indexed; references to other schemas are always indexed.

The first declared schema becomes the main schema (the schema of the data to be scanned.) The main schema may also be set by schema= schema;. schema.delimiter="delimiter"; sets the delimiter for schema and schema .input="file"; sets the input to file. The default delimiter is ";". The main schema input is the data command line argument if specified. Otherwise schema input file names are determined by the schema name with an optional .db suffix. Multiple schemas may be placed in a single file using the pax(1) vdb archive format.

EXPRESSIONS

A labelled expression is defined by one of: label : statement-list type label() { statement-list }

Supported expression labels are:

action

Evaluated for each record in which select returns non-zero. The default action lists each selected record as it appears in the databse.
begin

Evaluated once before the traversal begins. The return value is ignored.
end
Evaluated once after the traversal ends. The return value is ignored.
select

Evaluated once for each record. If the return value is non-zero then action is evaluated. The default select return value is always non-zero.
closure

TBD
loop
TBD

select is assumed when label: or type label() is omitted. statement-list is composed of expr(3) C style expressions, including int variable, ... and float variable, ... declarations, (int) and (float) casts, if - else conditionals, for and while loops, and { ... } blocks. The trailing ; in any expression is optional. In the absense of a return statement the expression value is the value of the last evaluated expression in statement-list. Numbers and comments follow C syntax. String operands must be quoted with either "..." or '...'. String comparisons (== and !=) treat the right hand operand as a ksh(1) file match pattern.

The expressions operate on the fields in the current input record. The begin and end expressions operate on a null valued current record. If a date_t type field is an operand to a binary operator then the other operand may be a string that is interpreted as a date(1) date expression; there is similar treatment for other types with alternate string representations.

There is also a predefined readonly schema with the following elements:

elapsed_t clock

The elapsed time in 1/100 seconds since this cql started.
date_t date

The date when this cql started.
int errors

The current soft error count. cql continues after a soft error but exits with a non-zero exit status when complete.
int line

The current input file line number.
int offset

The current input file byte offset.
int record

The current input file record number.
int select

The current number of selected records.
int size

The size in bytes of the current input record.
date_t time

The current date and time.

The following expr(3) functions are also supported:
cql.getenv(name)

Returns the value of the environment variable name. The empty string is returned for undefined environment variables.
cql.path(name,len)

Truncates the file pathname name to len bytes. cql.sub(string,old,new,flags)?Returns the substituted value of string the first match of the egrep(1) style regular expression old replaced by new. flags may be any combination of:
g
Substitute all matches of old.
l
Convert matches to lower case.
u
Convert matches to upper case.
exit(expr)

Causes cql to exit with the exit code expr. expr defaults to 0 if omitted.
printf(format[,arg...])

Print the arguments on stdout using the printf(3) specification format.
eprintf(format[,arg...])

Like printf but output goes to stderr .
query(format[,arg...])

Prompt with the printf(3) message on stderr for an interactive response. A line beginning with y returns 1, q or EOF causes cql to exit immediately, and any other input returns 0.

SEE ALSO

awk(1), grep(1), ksh(1), pax(1), perl(1), tw(1), expr(3), printf(3), tm(3)

IMPLEMENTATION

version

cql (AT&T Research) 2002-09-06
author

Glenn Fowler <glenn.s.fowler@gmail.com>
copyright

Copyright © 1991-2012 AT&T Intellectual Property
license

http://www.eclipse.org/org/documents/epl-v10.html