TCADB(3)

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version 1.4.48 · 2 versions
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✨ NAME ✨

okay so this is TCADB(3) from Tokyo Cabinet, and it's all about tcadb — the abstract database API. 💖

💖 DESCRIPTION 💖

bestie, the abstract database is literally a set of interfaces that lets you use on-memory hash database, on-memory tree database, hash database, B+ tree database, fixed-length database, and table database with the same API. No cap. One API, whole squad of databases. ✨

To use the abstract database API, include tcutil.h, tcadb.h, and related standard header files. Usually, write the following description near the front of a source file.

#include <tcutil.h>
#include <tcadb.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdint.h>

Objects whose type is pointer to TCADB are used to handle abstract databases. An abstract database object is created with the function tcadbnew and is deleted with the function tcadbdel. To avoid memory leak, it is important to delete every object when it is no longer in use. 🫶

Before operations to store or retrieve records, it is necessary to connect the abstract database object to the concrete one. The function tcadbopen is used to open a concrete database and the function tcadbclose is used to close the database. To avoid data missing or corruption, it is important to close every database instance when it is no longer in use. It is forbidden for multiple database objects in a process to open the same database at the same time. 💀

🌈 API 🌈

here we go, function by function, no skips, periodt. 💅

tcadbnew

The function tcadbnew is used in order to create an abstract database object.

TCADB *tcadbnew(void);

The return value is the new abstract database object. 🎀

tcadbdel

The function tcadbdel is used in order to delete an abstract database object.

void tcadbdel(TCADB *adb);
  • adb — specifies the abstract database object.

tcadbopen

The function tcadbopen is used in order to open an abstract database.

bool tcadbopen(TCADB *adb, const char *name);
  • adb — specifies the abstract database object.
  • name — specifies the name of the database. Here's the tea:
    • If it is "*", the database will be an on-memory hash database.
    • If it is "+", the database will be an on-memory tree database.
    • If its suffix is ".tch", the database will be a hash database.
    • If its suffix is ".tcb", the database will be a B+ tree database.
    • If its suffix is ".tcf", the database will be a fixed-length database.
    • If its suffix is ".tct", the database will be a table database.
    • Otherwise, this function fails. 🙈

Tuning parameters can trail the name, separated by "#". Each parameter is composed of the name and the value, separated by "=".

  • On-memory hash database supports "bnum", "capnum", and "capsiz".
  • On-memory tree database supports "capnum" and "capsiz".
  • Hash database supports "mode", "bnum", "apow", "fpow", "opts", "rcnum", "xmsiz", and "dfunit".
  • B+ tree database supports "mode", "lmemb", "nmemb", "bnum", "apow", "fpow", "opts", "lcnum", "ncnum", "xmsiz", and "dfunit".
  • Fixed-length database supports "mode", "width", and "limsiz".
  • Table database supports "mode", "bnum", "apow", "fpow", "opts", "rcnum", "lcnum", "ncnum", "xmsiz", "dfunit", and "idx".

If successful, the return value is true, else, it is false.

  • The tuning parameter "capnum" specifies the capacity number of records.
  • "capsiz" specifies the capacity size of using memory.
  • Records spilled the capacity are removed by the storing order.
  • "mode" can contain "w" of writer, "r" of reader, "c" of creating, "t" of truncating, "e" of no locking, and "f" of non-blocking lock. The default mode is relevant to "wc".
  • "opts" can contain "l" of large option, "d" of Deflate option, "b" of BZIP2 option, and "t" of TCBS option.
  • "idx" specifies the column name of an index and its type separated by ":". For example, "casket.tch#bnum=1000000#opts=ld" means that the name of the database file is "casket.tch", and the bucket number is 1000000, and the options are large and Deflate.

tcadbclose

The function tcadbclose is used in order to close an abstract database object.

bool tcadbclose(TCADB *adb);
  • adb — specifies the abstract 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. 😭

tcadbput

The function tcadbput is used in order to store a record into an abstract database object.

bool tcadbput(TCADB *adb, const void *kbuf, int ksiz, const void
*vbuf, int vsiz);
  • adb — specifies the abstract database object.
  • kbuf — specifies the pointer to the region of the key.
  • ksiz — specifies the size of the region of the key.
  • vbuf — specifies the pointer to the region of the value.
  • vsiz — specifies the size of the region of the value.

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.

tcadbput2

The function tcadbput2 is used in order to store a string record into an abstract object.

bool tcadbput2(TCADB *adb, const char *kstr, const char *vstr);
  • adb — specifies the abstract database object.
  • kstr — specifies the string of the key.
  • vstr — specifies the string of the value.

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.

tcadbputkeep

The function tcadbputkeep is used in order to store a new record into an abstract database object.

bool tcadbputkeep(TCADB *adb, const void *kbuf, int ksiz, const
void *vbuf, int vsiz);
  • adb — specifies the abstract database object.
  • kbuf — specifies the pointer to the region of the key.
  • ksiz — specifies the size of the region of the key.
  • vbuf — specifies the pointer to the region of the value.
  • vsiz — specifies the size of the region of the value.

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.

tcadbputkeep2

The function tcadbputkeep2 is used in order to store a new string record into an abstract database object.

bool tcadbputkeep2(TCADB *adb, const char *kstr, const char
*vstr);
  • adb — specifies the abstract database object.
  • kstr — specifies the string of the key.
  • vstr — specifies the string of the value.

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.

tcadbputcat

The function tcadbputcat is used in order to concatenate a value at the end of the existing record in an abstract database object.

bool tcadbputcat(TCADB *adb, const void *kbuf, int ksiz, const
void *vbuf, int vsiz);
  • adb — specifies the abstract database object.
  • kbuf — specifies the pointer to the region of the key.
  • ksiz — specifies the size of the region of the key.
  • vbuf — specifies the pointer to the region of the value.
  • vsiz — specifies the size of the region of the value.

If successful, the return value is true, else, it is false.

If there is no corresponding record, a new record is created.

tcadbputcat2

The function tcadbputcat2 is used in order to concatenate a string value at the end of the existing record in an abstract database object.

bool tcadbputcat2(TCADB *adb, const char *kstr, const char
*vstr);
  • adb — specifies the abstract database object.
  • kstr — specifies the string of the key.
  • vstr — specifies the string of the value.

If successful, the return value is true, else, it is false.

If there is no corresponding record, a new record is created.

tcadbout

The function tcadbout is used in order to remove a record of an abstract database object.

bool tcadbout(TCADB *adb, const void *kbuf, int ksiz);
  • adb — specifies the abstract database object.
  • kbuf — specifies the pointer to the region of the key.
  • ksiz — specifies the size of the region of the key.

If successful, the return value is true, else, it is false.

tcadbout2

The function tcadbout2 is used in order to remove a string record of an abstract database object.

bool tcadbout2(TCADB *adb, const char *kstr);
  • adb — specifies the abstract database object.
  • kstr — specifies the string of the key.

If successful, the return value is true, else, it is false.

tcadbget

The function tcadbget is used in order to retrieve a record in an abstract database object.

void *tcadbget(TCADB *adb, const void *kbuf, int ksiz, int *sp);
  • adb — specifies the abstract database object.
  • kbuf — specifies the pointer to the region of the key.
  • ksiz — specifies the size of the region of the 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 value 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.

tcadbget2

The function tcadbget2 is used in order to retrieve a string record in an abstract database object.

💖 tcadbget2

char *tcadbget2(TCADB *adb, const char *kstr);
  • adb — the abstract database object, bestie.
  • kstr — the string of the key.

If it works, you get back the string of the value of the corresponding record. If literally no record matches, you get NULL. 😭

Heads up: that returned region was allocated with the malloc call, so you gotta release it with the free call once you're done with it. No leaks, we're not doing that. 💅

🌸 tcadbvsiz

This one's for finding out the size of the value of a record in an abstract database object.

int tcadbvsiz(TCADB *adb, const void *kbuf, int ksiz);
  • adb — the abstract database object.
  • kbuf — pointer to the region of the key.
  • ksiz — size of the region of the key.

If successful, the return value is the size of the value of the corresponding record. Otherwise? -1. 💀

🦋 tcadbvsiz2

Same energy, but for the size of the value of a string record.

int tcadbvsiz2(TCADB *adb, const char *kstr);
  • adb — the abstract database object.
  • kstr — the string of the key.

If successful, the return value is the size of the value of the corresponding record, else it's -1.

✨ tcadbiterinit

Kicks off the iterator of an abstract database object.

bool tcadbiterinit(TCADB *adb);
  • adb — the abstract database object.

If successful, the return value is true, else it's false.

The iterator is what you use to access the key of every single record stored in a database. Main character access method, honestly. 👑

🎀 tcadbiternext

Gets the next key out of the iterator.

void *tcadbiternext(TCADB *adb, int *sp);
  • adb — the abstract database object.
  • sp — pointer to the variable that the size of the region of the return value gets assigned into.

If successful, the return value is the pointer to the region of the next key, else it's NULL. And NULL is also what you get when there's no record left to get out of the iterator.

Because an additional zero code is appended at the end of the region of the return value, you can treat the return value as a character string. Also, that region was allocated with the malloc call, so please release it with the free call when you're done. 🫶

You can access every record by just iterating calls to 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. And 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. So don't come for me about order, okay? 🙈

💜 tcadbiternext2

Grabs the next key string of the iterator.

char *tcadbiternext2(TCADB *adb);
  • adb — the abstract database object.

If successful, the return value is the string of the next key, else it's NULL. NULL shows up when no record is to be get out of the iterator.

That region was allocated with the malloc call, so release it with the free call when it is no longer in use. 🧚

You can access every record by iterating calls to this function. However, it is not assured if updating the database is occurred while the iteration. And again — 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.

🔥 tcadbfwmkeys

Gets forward matching keys in an abstract database object.

TCLIST *tcadbfwmkeys(TCADB *adb, const void *pbuf, int psiz, int max);
  • adb — the abstract database object.
  • pbuf — pointer to the region of the prefix.
  • psiz — size of the region of the prefix.
  • max — the maximum number of keys to be fetched. If it's 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. Iconic reliability, honestly. 💅

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. Like, it's doing the most. Be aware.

🌈 tcadbfwmkeys2

Forward matching string keys, same vibe.

TCLIST *tcadbfwmkeys2(TCADB *adb, const char *pstr, int max);
  • adb — the abstract database object.
  • pstr — the string of the prefix.
  • max — the maximum number of keys to be fetched. If it's negative, no limit is specified.

Return value is a list object of the corresponding keys. This function does never fail, and it returns an empty list even if no key corresponds.

Created with tclistnew, so delete it with tclistdel when it is no longer in use.
Note that this function may be very slow because every key in the database is scanned. Fr fr.

⭐ tcadbaddint

Adds an integer to a record.

int tcadbaddint(TCADB *adb, const void *kbuf, int ksiz, int num);
  • adb — the abstract database object.
  • kbuf — pointer to the region of the key.
  • ksiz — size of the region of the key.
  • num — the additional value.

If successful, the return value is the summation value, else it's INT_MIN. 😭

If the corresponding record exists, the value is treated as an integer and is added to. If no record corresponds, a new record of the additional value is stored. Simple as that. 🍓

💖 tcadbadddouble

Adds a real number to a record.

double tcadbadddouble(TCADB *adb, const void *kbuf, int ksiz, double num);
  • adb — the abstract database object.
  • kbuf — pointer to the region of the key.
  • ksiz — size of the region of the key.
  • num — the additional value.

If successful, the return value is the summation value, else it's Not-a-Number. 💀

If the corresponding record exists, the value is treated as a real number and is added to. If no record corresponds, a new record of the additional value is stored.

🎀 tcadbsync

Syncs up the updated contents of an abstract database object with the file and the device. Glow up for your data. ✨

bool tcadbsync(TCADB *adb);
  • adb — the abstract database object.

If successful, the return value is true, else it's false.

👑 tcadboptimize

Optimizes the storage of an abstract database object.

bool tcadboptimize(TCADB *adb, const char *params);
  • adb — the abstract database object.
  • params — the string of the tuning parameters, which works as with the tuning of parameters the function tcadbopen. If it's NULL, it is not used.

If successful, the return value is true, else it's false.

This function is useful to reduce the size of the database storage with data fragmentation by successive updating. Basically a deep-clean for your db. 🧹

🦋 tcadbvanish

Removes all records of an abstract database object. Poof. Gone. ✨

bool tcadbvanish(TCADB *adb);
  • adb — the abstract database object.

If successful, the return value is true, else it's false.

🌸 tcadbcopy

Copies the database file of an abstract database object.

bool tcadbcopy(TCADB *adb, const char *path);
  • adb — the abstract database object.
  • path — 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's 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. Backup bestie behavior. 🫶

💜 tcadbtranbegin

Begins the transaction of an abstract database object.

bool tcadbtranbegin(TCADB *adb);
  • adb — the abstract database object.

If successful, the return value is true, else it's 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. All updated regions are kept track of by write ahead logging while the transaction.

If the database is closed during transaction, the transaction is aborted implicitly. So, like, don't do that. 😭

🌸 tcadbtrancommit — the "we're keeping this" button

The function tcadbtrancommit is used in order to commit the transaction of an abstract database object.

bool tcadbtrancommit(TCADB *adb);
  • adb specifies the abstract database object.
  • If successful, the return value is true, else, it is false.
  • Update in the transaction is fixed when it is committed successfully.
no takebacks after this one bestie 💅 once it commits, it's fixed.

🫶 tcadbtranabort — the "jk nvm" button

The function tcadbtranabort is used in order to abort the transaction of an abstract database object.

bool tcadbtranabort(TCADB *adb);
  • adb specifies the abstract database object.
  • 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.
it's giving time travel ✨ everything you did in the transaction just… poof. gone. back to before, periodt.

🦋 tcadbpath — where does this thing even live

The function tcadbpath is used in order to get the file path of an abstract database object.

const char *tcadbpath(TCADB *adb);
  • adb specifies the abstract database object.
  • The return value is the path of the database file or NULL if the object does not connect to any database.
  • "*" stands for on-memory hash database. "+" stands for on-memory tree database.
so if you get "*" or "+" back, that's not a real file path bestie, that's the on-memory vibe — hash and tree respectively 👑

🎀 tcadbrnum — how many records we got

The function tcadbrnum is used in order to get the number of records of an abstract database object.

uint64_t tcadbrnum(TCADB *adb);
  • adb specifies the abstract database object.
  • The return value is the number of records or 0 if the object does not connect to any database instance.

⭐ tcadbsize — how thicc is this database

The function tcadbsize is used in order to get the size of the database of an abstract database object.

uint64_t tcadbsize(TCADB *adb);
  • adb specifies the abstract database object.
  • The return value is the size of the database or 0 if the object does not connect to any database instance.

🌈 tcadbmisc — the everything bagel function

The function tcadbmisc is used in order to call a versatile function for miscellaneous operations of an abstract database object.

TCLIST *tcadbmisc(TCADB *adb, const char *name, const TCLIST *args);
  • adb specifies the abstract database object.
  • name specifies the name of the function. All databases support "put", "out", "get", "putlist", "outlist", "getlist", and "getpart".

Okay so here's the whole menu, and yes we're going through every single one because they all matter 💖:

  • "put" is to store a record. It receives a key and a value, and returns an empty list.
  • "out" is to remove a record. It receives a key, and returns an empty list.
  • "get" is to retrieve a record. It receives a key, and returns a list of the values.
  • "putlist" is to store records. It receives keys and values one after the other, and returns an empty list.
  • "outlist" is to remove records. It receives keys, and returns an empty list.
  • "getlist" is to retrieve records. It receives keys, and returns keys and values of corresponding records one after the other.
  • "getpart" is to retrieve the partial value of a record. It receives a key, the offset of the region, and the length of the region.
  • args specifies a list object containing arguments.
  • If successful, the return value is a list object of the result. NULL is returned on failure.
  • 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 MEMORY LEAK JUMPSCARE 😭 fr fr, you called tclistnew so you owe it a tclistdel. don't leave it hanging, that's not main character energy.

✨ SEE ALSO ✨

and that's a wrap on TCADB(3) bestie 🎀 this one came from the Man Page collection, dated 2012-08-18, and yeah she's been iconic since day one 👑 go forth and commit (responsibly) 💖✨

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