API¶
The function `tctdberrmsg' is used in order to get the message
    string corresponding to an error code.
const char *tctdberrmsg(int ecode);
`ecode' specifies the error code.
The return value is the message string of the error
  code.
 
The function `tctdbnew' is used in order to create a table
    database object.
TCTDB *tctdbnew(void);
The return value is the new table database object.
 
The function `tctdbdel' is used in order to delete a table
    database object.
void tctdbdel(TCTDB *tdb);
`tdb' specifies the table database object.
If the database is not closed, it is closed implicitly.
  Note that the deleted object and its derivatives can not be used
  anymore.
 
The function `tctdbecode' is used in order to get the last
    happened error code of a table database object.
int tctdbecode(TCTDB *tdb);
`tdb' specifies the table database object.
The return value is the last happened error code.
The following error codes are defined: `TCESUCCESS' for
  success, `TCETHREAD' for threading error, `TCEINVALID' for invalid operation,
  `TCENOFILE' for file not found, `TCENOPERM' for no permission, `TCEMETA' for
  invalid meta data, `TCERHEAD' for invalid record header, `TCEOPEN' for open
  error, `TCECLOSE' for close error, `TCETRUNC' for trunc error, `TCESYNC' for
  sync error, `TCESTAT' for stat error, `TCESEEK' for seek error, `TCEREAD' for
  read error, `TCEWRITE' for write error, `TCEMMAP' for mmap error, `TCELOCK'
  for lock error, `TCEUNLINK' for unlink error, `TCERENAME' for rename error,
  `TCEMKDIR' for mkdir error, `TCERMDIR' for rmdir error, `TCEKEEP' for existing
  record, `TCENOREC' for no record found, and `TCEMISC' for miscellaneous
  error.
 
The function `tctdbsetmutex' is used in order to set mutual
    exclusion control of a table database object for threading.
bool tctdbsetmutex(TCTDB *tdb);
`tdb' specifies the table database object which is
  not opened.
If successful, the return value is true, else, it is
  false.
Note that the mutual exclusion control is needed if the
  object is shared by plural threads and this function should be called before
  the database is opened.
 
The function `tctdbtune' is used in order to set the tuning
    parameters of a table database object.
bool tctdbtune(TCTDB *tdb, int64_t bnum, int8_t
  apow, int8_t fpow, uint8_t
  opts);
`tdb' specifies the table database object which is
  not opened.
`bnum' specifies the number of elements of the
  bucket array. If it is not more than 0, the default value is specified. The
  default value is 131071. Suggested size of the bucket array is about from 0.5
  to 4 times of the number of all records to be stored.
`apow' specifies the size of record alignment by
  power of 2. If it is negative, the default value is specified. The default
  value is 4 standing for 2^4=16.
`fpow' specifies the maximum number of elements of
  the free block pool by power of 2. If it is negative, the default value is
  specified. The default value is 10 standing for 2^10=1024.
`opts' specifies options by bitwise-or:
  `TDBTLARGE' specifies that the size of the database can be larger than 2GB by
  using 64-bit bucket array, `TDBTDEFLATE' specifies that each record is
  compressed with Deflate encoding, `TDBTBZIP' specifies that each record is
  compressed with BZIP2 encoding, `TDBTTCBS' specifies that each record is
  compressed with TCBS encoding.
If successful, the return value is true, else, it is
  false.
Note that the tuning parameters should be set before the
  database is opened.
 
The function `tctdbsetcache' is set the caching parameters of a
    table database object.
bool tctdbsetcache(TCTDB *tdb, int32_t rcnum,
  int32_t lcnum, int32_t ncnum);
`tdb' specifies the table database object which is
  not opened.
`rcnum' specifies the maximum number of records to
  be cached. If it is not more than 0, the record cache is disabled. It is
  disabled by default.
`lcnum' specifies the maximum number of leaf nodes
  to be cached. If it is not more than 0, the default value is specified. The
  default value is 4096.
`ncnum' specifies the maximum number of non-leaf
  nodes to be cached. If it is not more than 0, the default value is specified.
  The default value is 512.
If successful, the return value is true, else, it is
  false.
Note that the caching parameters should be set before the
  database is opened. Leaf nodes and non-leaf nodes are used in column
  indices.
 
The function `tctdbsetxmsiz' is used in order to set the size of
    the extra mapped memory of a table database object.
bool tctdbsetxmsiz(TCTDB *tdb, int64_t
  xmsiz);
`tdb' specifies the table database object which is
  not opened.
`xmsiz' specifies the size of the extra mapped
  memory. If it is not more than 0, the extra mapped memory is disabled. The
  default size is 67108864.
If successful, the return value is true, else, it is
  false.
Note that the mapping parameters should be set before the
  database is opened.
 
The function `tctdbsetdfunit' is used in order to set the unit
    step number of auto defragmentation of a table database object.
bool tctdbsetdfunit(TCTDB *tdb, int32_t
  dfunit);
`tdb' specifies the table database object which is
  not opened.
`dfunit' specifie the unit step number. If it is
  not more than 0, the auto defragmentation is disabled. It is disabled by
  default.
If successful, the return value is true, else, it is
  false.
Note that the defragmentation parameters should be set
  before the database is opened.
 
The function `tctdbopen' is used in order to open a database file
    and connect a table database object.
bool tctdbopen(TCTDB *tdb, const char *path, int
  omode);
`tdb' specifies the table database object which is
  not opened.
`path' specifies the path of the database
  file.
`omode' specifies the connection mode:
  `TDBOWRITER' as a writer, `TDBOREADER' as a reader. If the mode is
  `TDBOWRITER', the following may be added by bitwise-or: `TDBOCREAT', which
  means it creates a new database if not exist, `TDBOTRUNC', which means it
  creates a new database regardless if one exists, `TDBOTSYNC', which means
  every transaction synchronizes updated contents with the device. Both of
  `TDBOREADER' and `TDBOWRITER' can be added to by bitwise-or: `TDBONOLCK',
  which means it opens the database file without file locking, or `TDBOLCKNB',
  which means locking is performed without blocking.
If successful, the return value is true, else, it is
  false.
 
The function `tctdbclose' is used in order to close a table
    database object.
bool tctdbclose(TCTDB *tdb);
`tdb' specifies the table database object.
If successful, the return value is true, else, it is
  false.
Update of a database is assured to be written when the
  database is closed. If a writer opens a database but does not close it
  appropriately, the database will be broken.
 
The function `tctdbput' is used in order to store a record into a
    table database object.
bool tctdbput(TCTDB *tdb, const void *pkbuf, int
  pksiz, TCMAP *cols);
`tdb' specifies the table database object
  connected as a writer.
`pkbuf' specifies the pointer to the region of the
  primary key.
`pksiz' specifies the size of the region of the
  primary key.
`cols' specifies a map object containing
  columns.
If successful, the return value is true, else, it is
  false.
If a record with the same key exists in the database, it
  is overwritten.
 
The function `tctdbput2' is used in order to store a string record
    into a table database object with a zero separated column string.
bool tctdbput2(TCTDB *tdb, const void *pkbuf, int
  pksiz, const void *cbuf, int
  csiz);
`tdb' specifies the table database object
  connected as a writer.
`pkbuf' specifies the pointer to the region of the
  primary key.
`pksiz' specifies the size of the region of the
  primary key.
`cbuf' specifies the pointer to the region of the
  zero separated column string where the name and the value of each column are
  situated one after the other.
`csiz' specifies the size of the region of the
  column string.
If successful, the return value is true, else, it is
  false.
If a record with the same key exists in the database, it
  is overwritten.
 
The function `tctdbput3' is used in order to store a string record
    into a table database object with a tab separated column string.
bool tctdbput3(TCTDB *tdb, const char *pkstr,
  const char *cstr);
`tdb' specifies the table database object
  connected as a writer.
`pkstr' specifies the string of the primary
  key.
`cstr' specifies the string of the the tab
  separated column string where the name and the value of each column are
  situated one after the other.
If successful, the return value is true, else, it is
  false.
If a record with the same key exists in the database, it
  is overwritten.
 
The function `tctdbputkeep' is used in order to store a new record
    into a table database object.
bool tctdbputkeep(TCTDB *tdb, const void *pkbuf,
  int pksiz, TCMAP *cols);
`tdb' specifies the table database object
  connected as a writer.
`pkbuf' specifies the pointer to the region of the
  primary key.
`pksiz' specifies the size of the region of the
  primary key.
`cols' specifies a map object containing
  columns.
If successful, the return value is true, else, it is
  false.
If a record with the same key exists in the database,
  this function has no effect.
 
The function `tctdbputkeep2' is used in order to store a new
    string record into a table database object with a zero separated column
    string.
bool tctdbputkeep2(TCTDB *tdb, const void *pkbuf,
  int pksiz, const void *cbuf, int
  csiz);
`tdb' specifies the table database object
  connected as a writer.
`pkbuf' specifies the pointer to the region of the
  primary key.
`pksiz' specifies the size of the region of the
  primary key.
`cbuf' specifies the pointer to the region of the
  zero separated column string where the name and the value of each column are
  situated one after the other.
`csiz' specifies the size of the region of the
  column string.
If successful, the return value is true, else, it is
  false.
If a record with the same key exists in the database,
  this function has no effect.
 
The function `tctdbputkeep3' is used in order to store a new
    string record into a table database object with a tab separated column
    string.
bool tctdbputkeep3(TCTDB *tdb, const char *pkstr,
  const char *cstr);
`tdb' specifies the table database object
  connected as a writer.
`pkstr' specifies the string of the primary
  key.
`cstr' specifies the string of the the tab
  separated column string where the name and the value of each column are
  situated one after the other.
If successful, the return value is true, else, it is
  false.
If a record with the same key exists in the database,
  this function has no effect.
 
The function `tctdbputcat' is used in order to concatenate columns
    of the existing record in a table database object.
bool tctdbputcat(TCTDB *tdb, const void *pkbuf,
  int pksiz, TCMAP *cols);
`tdb' specifies the table database object
  connected as a writer.
`pkbuf' specifies the pointer to the region of the
  primary key.
`pksiz' specifies the size of the region of the
  primary key.
`cols' specifies a map object containing
  columns.
If successful, the return value is true, else, it is
  false.
If there is no corresponding record, a new record is
  created.
 
The function `tctdbputcat2' is used in order to concatenate
    columns in a table database object with a zero separated column string.
bool tctdbputcat2(TCTDB *tdb, const void *pkbuf,
  int pksiz, const void *cbuf, int
  csiz);
`tdb' specifies the table database object
  connected as a writer.
`pkbuf' specifies the pointer to the region of the
  primary key.
`pksiz' specifies the size of the region of the
  primary key.
`cbuf' specifies the pointer to the region of the
  zero separated column string where the name and the value of each column are
  situated one after the other.
`csiz' specifies the size of the region of the
  column string.
If successful, the return value is true, else, it is
  false.
If there is no corresponding record, a new record is
  created.
 
The function `tctdbputcat3' is used in order to concatenate
    columns in a table database object with with a tab separated column
  string.
bool tctdbputcat3(TCTDB *tdb, const char *pkstr,
  const char *cstr);
`tdb' specifies the table database object
  connected as a writer.
`pkstr' specifies the string of the primary
  key.
`cstr' specifies the string of the the tab
  separated column string where the name and the value of each column are
  situated one after the other.
If successful, the return value is true, else, it is
  false.
If there is no corresponding record, a new record is
  created.
 
The function `tctdbout' is used in order to remove a record of a
    table database object.
bool tctdbout(TCTDB *tdb, const void *pkbuf, int
  pksiz);
`tdb' specifies the table database object
  connected as a writer.
`pkbuf' specifies the pointer to the region of the
  primary key.
`pksiz' specifies the size of the region of the
  primary key.
If successful, the return value is true, else, it is
  false.
 
The function `tctdbout2' is used in order to remove a string
    record of a table database object.
bool tctdbout2(TCTDB *tdb, const char
  *pkstr);
`tdb' specifies the table database object
  connected as a writer.
`pkstr' specifies the string of the primary
  key.
If successful, the return value is true, else, it is
  false.
 
The function `tctdbget' is used in order to retrieve a record in a
    table database object.
TCMAP *tctdbget(TCTDB *tdb, const void *pkbuf,
  int pksiz);
`tdb' specifies the table database object.
`pkbuf' specifies the pointer to the region of the
  primary key.
`pksiz' specifies the size of the region of the
  primary key.
If successful, the return value is a map object of the
  columns of the corresponding record. `NULL' is returned if no record
  corresponds.
Because the object of the return value is created with
  the function `tcmapnew', it should be deleted with the function `tcmapdel'
  when it is no longer in use.
 
The function `tctdbget2' is used in order to retrieve a record in
    a table database object as a zero separated column string.
char *tctdbget2(TCTDB *tdb, const void *pkbuf,
  int pksiz, int *sp);
`tdb' specifies the table database object.
`pkbuf' specifies the pointer to the region of the
  primary key.
`pksiz' specifies the size of the region of the
  primary key.
`sp' specifies the pointer to the variable into
  which the size of the region of the return value is assigned.
If successful, the return value is the pointer to the
  region of the column string of the corresponding record. `NULL' is returned if
  no record corresponds.
Because an additional zero code is appended at the end of
  the region of the return value, the return value can be treated as a character
  string. Because the region of the return value is allocated with the `malloc'
  call, it should be released with the `free' call when it is no longer in
  use.
 
The function `tctdbget3' is used in order to retrieve a string
    record in a table database object as a tab separated column string.
char *tctdbget3(TCTDB *tdb, const char
  *pkstr);
`tdb' specifies the table database object.
`pkstr' specifies the string of the primary
  key.
If successful, the return value is the tab separated
  column string of the corresponding record. `NULL' is returned if no record
  corresponds.
Because the region of the return value is allocated with
  the `malloc' call, it should be released with the `free' call when it is no
  longer in use.
 
The function `tctdbvsiz' is used in order to get the size of the
    value of a record in a table database object.
int tctdbvsiz(TCTDB *tdb, const void *pkbuf, int
  pksiz);
`tdb' specifies the table database object.
`kbuf' specifies the pointer to the region of the
  primary key.
`ksiz' specifies the size of the region of the
  primary key.
If successful, the return value is the size of the value
  of the corresponding record, else, it is -1.
 
The function `tctdbvsiz2' is used in order to get the size of the
    value of a string record in a table database object.
int tctdbvsiz2(TCTDB *tdb, const char
  *pkstr);
`tdb' specifies the table database object.
`kstr' specifies the string of the primary
  key.
If successful, the return value is the size of the value
  of the corresponding record, else, it is -1.
 
The function `tctdbiterinit' is used in order to initialize the
    iterator of a table database object.
bool tctdbiterinit(TCTDB *tdb);
`tdb' specifies the table database object.
If successful, the return value is true, else, it is
  false.
The iterator is used in order to access the primary key
  of every record stored in a database.
 
The function `tctdbiternext' is used in order to get the next
    primary key of the iterator of a table database object.
void *tctdbiternext(TCTDB *tdb, int *sp);
`tdb' specifies the table database object.
`sp' specifies the pointer to the variable into
  which the size of the region of the return value is assigned.
If successful, the return value is the pointer to the
  region of the next primary key, else, it is `NULL'. `NULL' is returned when no
  record is to be get out of the iterator.
Because an additional zero code is appended at the end of
  the region of the return value, the return value can be treated as a character
  string. Because the region of the return value is allocated with the `malloc'
  call, it should be released with the `free' call when it is no longer in use.
  It is possible to access every record by iteration of calling this function.
  It is allowed to update or remove records whose keys are fetched while the
  iteration. However, it is not assured if updating the database is occurred
  while the iteration. Besides, the order of this traversal access method is
  arbitrary, so it is not assured that the order of storing matches the one of
  the traversal access.
 
The function `tctdbiternext2' is used in order to get the next
    primary key string of the iterator of a table database object.
char *tctdbiternext2(TCTDB *tdb);
`tdb' specifies the table database object.
If successful, the return value is the string of the next
  primary key, else, it is `NULL'. `NULL' is returned when no record is to be
  get out of the iterator.
Because the region of the return value is allocated with
  the `malloc' call, it should be released with the `free' call when it is no
  longer in use. It is possible to access every record by iteration of calling
  this function. However, it is not assured if updating the database is occurred
  while the iteration. Besides, the order of this traversal access method is
  arbitrary, so it is not assured that the order of storing matches the one of
  the traversal access.
 
The function `tctdbiternext3' is used in order to get the columns
    of the next record of the iterator of a table database object.
TCMAP *tctdbiternext3(TCTDB *tdb);
`tdb' specifies the table database object.
If successful, the return value is a map object of the
  columns of the next record, else, it is `NULL'. `NULL' is returned when no
  record is to be get out of the iterator. The primary key is added into the map
  as a column of an empty string key.
Because the object of the return value is created with
  the function `tcmapnew', it should be deleted with the function `tcmapdel'
  when it is no longer in use. It is possible to access every record by
  iteration of calling this function. However, it is not assured if updating the
  database is occurred while the iteration. Besides, the order of this traversal
  access method is arbitrary, so it is not assured that the order of storing
  matches the one of the traversal access.
 
The function `tctdbfwmkeys' is used in order to get forward
    matching primary keys in a table database object.
TCLIST *tctdbfwmkeys(TCTDB *tdb, const void
  *pbuf, int psiz, int max);
`tdb' specifies the table database object.
`pbuf' specifies the pointer to the region of the
  prefix.
`psiz' specifies the size of the region of the
  prefix.
`max' specifies the maximum number of keys to be
  fetched. If it is negative, no limit is specified.
The return value is a list object of the corresponding
  keys. This function does never fail. It returns an empty list even if no key
  corresponds.
Because the object of the return value is created with
  the function `tclistnew', it should be deleted with the function `tclistdel'
  when it is no longer in use. Note that this function may be very slow because
  every key in the database is scanned.
 
The function `tctdbfwmkeys2' is used in order to get forward
    matching string primary keys in a table database object.
TCLIST *tctdbfwmkeys2(TCTDB *tdb, const char
  *pstr, int max);
`tdb' specifies the table database object.
`pstr' specifies the string of the prefix.
`max' specifies the maximum number of keys to be
  fetched. If it is negative, no limit is specified.
The return value is a list object of the corresponding
  keys. This function does never fail. It returns an empty list even if no key
  corresponds.
Because the object of the return value is created with
  the function `tclistnew', it should be deleted with the function `tclistdel'
  when it is no longer in use. Note that this function may be very slow because
  every key in the database is scanned.
 
The function `tctdbaddint' is used in order to add an integer to a
    column of a record in a table database object.
int tctdbaddint(TCTDB *tdb, const void *pkbuf,
  int pksiz, int num);
`tdb' specifies the table database object
  connected as a writer.
`kbuf' specifies the pointer to the region of the
  primary key.
`ksiz' specifies the size of the region of the
  primary key.
`num' specifies the additional value.
If successful, the return value is the summation value,
  else, it is `INT_MIN'.
The additional value is stored as a decimal string value
  of a column whose name is "_num". If no record corresponds, a new
  record with the additional value is stored.
 
The function `tctdbadddouble' is used in order to add a real
    number to a column of a record in a table database object.
double tctdbadddouble(TCTDB *tdb, const void
  *pkbuf, int pksiz, double num);
`tdb' specifies the table database object
  connected as a writer.
`kbuf' specifies the pointer to the region of the
  primary key.
`ksiz' specifies the size of the region of the
  primary key.
`num' specifies the additional value.
If successful, the return value is the summation value,
  else, it is Not-a-Number.
The additional value is stored as a decimal string value
  of a column whose name is "_num". If no record corresponds, a new
  record with the additional value is stored.
 
The function `tctdbsync' is used in order to synchronize updated
    contents of a table database object with the file and the device.
bool tctdbsync(TCTDB *tdb);
`tdb' specifies the table database object
  connected as a writer.
If successful, the return value is true, else, it is
  false.
This function is useful when another process connects to
  the same database file.
 
The function `tctdboptimize' is used in order to optimize the file
    of a table database object.
bool tctdboptimize(TCTDB *tdb, int64_t bnum,
  int8_t apow, int8_t fpow, uint8_t
  opts);
`tdb' specifies the table database object
  connected as a writer.
`bnum' specifies the number of elements of the
  bucket array. If it is not more than 0, the default value is specified. The
  default value is two times of the number of records.
`apow' specifies the size of record alignment by
  power of 2. If it is negative, the current setting is not changed.
`fpow' specifies the maximum number of elements of
  the free block pool by power of 2. If it is negative, the current setting is
  not changed.
`opts' specifies options by bitwise-or:
  `TDBTLARGE' specifies that the size of the database can be larger than 2GB by
  using 64-bit bucket array, `TDBTDEFLATE' specifies that each record is
  compressed with Deflate encoding, `TDBTBZIP' specifies that each record is
  compressed with BZIP2 encoding, `TDBTTCBS' specifies that each record is
  compressed with TCBS encoding. If it is `UINT8_MAX', the current setting is
  not changed.
If successful, the return value is true, else, it is
  false.
This function is useful to reduce the size of the
  database file with data fragmentation by successive updating.
 
The function `tctdbvanish' is used in order to remove all records
    of a table database object.
bool tctdbvanish(TCTDB *tdb);
`tdb' specifies the table database object
  connected as a writer.
If successful, the return value is true, else, it is
  false.
 
The function `tctdbcopy' is used in order to copy the database
    file of a table database object.
bool tctdbcopy(TCTDB *tdb, const char *path);
`tdb' specifies the table database object.
`path' specifies the path of the destination file.
  If it begins with `@', the trailing substring is executed as a command
  line.
If successful, the return value is true, else, it is
  false. False is returned if the executed command returns non-zero code.
The database file is assured to be kept synchronized and
  not modified while the copying or executing operation is in progress. So, this
  function is useful to create a backup file of the database file.
 
The function `tctdbtranbegin' is used in order to begin the
    transaction of a table database object.
bool tctdbtranbegin(TCTDB *tdb);
`tdb' specifies the table database object
  connected as a writer.
If successful, the return value is true, else, it is
  false.
The database is locked by the thread while the
  transaction so that only one transaction can be activated with a database
  object at the same time. Thus, the serializable isolation level is assumed if
  every database operation is performed in the transaction. Because all pages
  are cached on memory while the transaction, the amount of referred records is
  limited by the memory capacity. If the database is closed during transaction,
  the transaction is aborted implicitly.
 
The function `tctdbtrancommit' is used in order to commit the
    transaction of a table database object.
bool tctdbtrancommit(TCTDB *tdb);
`tdb' specifies the table database object
  connected as a writer.
If successful, the return value is true, else, it is
  false.
Update in the transaction is fixed when it is committed
  successfully.
 
The function `tctdbtranabort' is used in order to abort the
    transaction of a table database object.
bool tctdbtranabort(TCTDB *tdb);
`tdb' specifies the table database object
  connected as a writer.
If successful, the return value is true, else, it is
  false.
Update in the transaction is discarded when it is
  aborted. The state of the database is rollbacked to before transaction.
 
The function `tctdbpath' is used in order to get the file path of
    a table database object.
const char *tctdbpath(TCTDB *tdb);
`tdb' specifies the table database object.
The return value is the path of the database file or
  `NULL' if the object does not connect to any database file.
 
The function `tctdbrnum' is used in order to get the number of
    records ccccof a table database object.
uint64_t tctdbrnum(TCTDB *tdb);
`tdb' specifies the table database object.
The return value is the number of records or 0 if the
  object does not connect to any database file.
 
The function `tctdbfsiz' is used in order to get the size of the
    database file of a table database object.
uint64_t tctdbfsiz(TCTDB *tdb);
`tdb' specifies the table database object.
The return value is the size of the database file or 0 if
  the object does not connect to any database file.
 
The function `tctdbsetindex' is used in order to set a column
    index to a table database object.
bool tctdbsetindex(TCTDB *tdb, const char *name,
  int type);
`tdb' specifies the table database object
  connected as a writer.
`name' specifies the name of a column. If the name
  of an existing index is specified, the index is rebuilt. An empty string means
  the primary key.
`type' specifies the index type: `TDBITLEXICAL'
  for lexical string, `TDBITDECIMAL' for decimal string, `TDBITTOKEN' for token
  inverted index, `TDBITQGRAM' for q-gram inverted index. If it is `TDBITOPT',
  the index is optimized. If it is `TDBITVOID', the index is removed. If
  `TDBITKEEP' is added by bitwise-or and the index exists, this function merely
  returns failure.
If successful, the return value is true, else, it is
  false.
Note that the setting indices should be set after the
  database is opened.
 
The function `tctdbgenuid' is used in order to generate a unique
    ID number of a table database object.
int64_t tctdbgenuid(TCTDB *tdb);
`tdb' specifies the table database object
  connected as a writer.
The return value is the new unique ID number or -1 on
  failure.
 
The function `tctdbqrynew' is used in order to create a query
    object.
TDBQRY *tctdbqrynew(TCTDB *tdb);
`tdb' specifies the table database object.
The return value is the new query object.
 
The function `tctdbqrydel' is used in order to delete a query
    object.
void tctdbqrydel(TDBQRY *qry);
`qry' specifies the query object.
 
The function `tctdbqryaddcond' is used in order to add a narrowing
    condition to a query object.
void tctdbqryaddcond(TDBQRY *qry, const char
  *name, int op, const char
  *expr);
`qry' specifies the query object.
`name' specifies the name of a column. An empty
  string means the primary key.
`op' specifies an operation type: `TDBQCSTREQ' for
  string which is equal to the expression, `TDBQCSTRINC' for string which is
  included in the expression, `TDBQCSTRBW' for string which begins with the
  expression, `TDBQCSTREW' for string which ends with the expression,
  `TDBQCSTRAND' for string which includes all tokens in the expression,
  `TDBQCSTROR' for string which includes at least one token in the expression,
  `TDBQCSTROREQ' for string which is equal to at least one token in the
  expression, `TDBQCSTRRX' for string which matches regular expressions of the
  expression, `TDBQCNUMEQ' for number which is equal to the expression,
  `TDBQCNUMGT' for number which is greater than the expression, `TDBQCNUMGE' for
  number which is greater than or equal to the expression, `TDBQCNUMLT' for
  number which is less than the expression, `TDBQCNUMLE' for number which is
  less than or equal to the expression, `TDBQCNUMBT' for number which is between
  two tokens of the expression, `TDBQCNUMOREQ' for number which is equal to at
  least one token in the expression, `TDBQCFTSPH' for full-text search with the
  phrase of the expression, `TDBQCFTSAND' for full-text search with all tokens
  in the expression, `TDBQCFTSOR' for full-text search with at least one token
  in the expression, `TDBQCFTSEX' for full-text search with the compound
  expression. All operations can be flagged by bitwise-or: `TDBQCNEGATE' for
  negation, `TDBQCNOIDX' for using no index.
`expr' specifies an operand exression.
 
The function `tctdbqrysetorder' is used in order to set the order
    of a query object.
void tctdbqrysetorder(TDBQRY *qry, const char
  *name, int type);
`qry' specifies the query object.
`name' specifies the name of a column. An empty
  string means the primary key.
`type' specifies the order type: `TDBQOSTRASC' for
  string ascending, `TDBQOSTRDESC' for string descending, `TDBQONUMASC' for
  number ascending, `TDBQONUMDESC' for number descending.
 
The function `tctdbqrysetlimit' is used in order to set the limit
    number of records of the result of a query object.
void tctdbqrysetlimit(TDBQRY *qry, int max, int
  skip);
`qry' specifies the query object.
`max' specifies the maximum number of records of
  the result. If it is negative, no limit is specified.
`skip' specifies the number of skipped records of
  the result. If it is not more than 0, no record is skipped.
 
The function `tctdbqrysearch' is used in order to execute the
    search of a query object.
TCLIST *tctdbqrysearch(TDBQRY *qry);
`qry' specifies the query object.
The return value is a list object of the primary keys of
  the corresponding records. This function does never fail. It returns an empty
  list even if no record corresponds.
Because the object of the return value is created with
  the function `tclistnew', it should be deleted with the function `tclistdel'
  when it is no longer in use.
 
The function `tctdbqrysearchout' is used in order to remove each
    record corresponding to a query object.
bool tctdbqrysearchout(TDBQRY *qry);
`qry' specifies the query object of the database
  connected as a writer.
If successful, the return value is true, else, it is
  false.
 
The function `tctdbqryproc' is used in order to process each
    record corresponding to a query object.
bool tctdbqryproc(TDBQRY *qry, TDBQRYPROC proc,
  void *op);
`qry' specifies the query object of the database
  connected as a writer.
`proc' specifies the pointer to the iterator
  function called for each record. It receives four parameters. The first
  parameter is the pointer to the region of the primary key. The second
  parameter is the size of the region of the primary key. The third parameter is
  a map object containing columns. The fourth parameter is the pointer to the
  optional opaque object. It returns flags of the post treatment by bitwise-or:
  `TDBQPPUT' to modify the record, `TDBQPOUT' to remove the record, `TDBQPSTOP'
  to stop the iteration.
`op' specifies an arbitrary pointer to be given as
  a parameter of the iterator function. If it is not needed, `NULL' can be
  specified.
If successful, the return value is true, else, it is
  false.
 
The function `tctdbqryhint' is used in order to get the hint
    string of a query object.
const char *tctdbqryhint(TDBQRY *qry);
`qry' specifies the query object.
The return value is the hint string.
 
The function `tctdbmetasearch' is used in order to retrieve
    records with multiple query objects and get the set of the result.
TCLIST *tctdbmetasearch(TDBQRY **qrys, int num,
  int type);
`qrys' specifies an array of the query
  objects.
`num' specifies the number of elements of the
  array.
`type' specifies a set operation type:
  `TDBMSUNION' for the union set, `TDBMSISECT' for the intersection set,
  `TDBMSDIFF' for the difference set.
The return value is a list object of the primary keys of
  the corresponding records. This function does never fail. It returns an empty
  list even if no record corresponds.
If the first query object has the order setting, the
  result array is sorted by the order. Because the object of the return value is
  created with the function `tclistnew', it should be deleted with the function
  `tclistdel' when it is no longer in use.