Database Management Library

Database Management Library (DBL)

Developer(s)	Rodrigo C. O. Rocha
Initial release	July 2, 2010 (2010-07-02)
Stable release	1.0 / July 2, 2010;12 years ago (2010-07-02)
Written in	C++
Type	Embedded RDBMS
License	GNU General Public License
Website	sites.google.com/site/rcorcs/download/library sourceforge.net/projects/dblibrary

Database Management Library (DBL) is a relational database management system (RDBMS) contained in a C++ programming library. The DBL source code is available under the terms of the GNU General Public License.

DBL was fully developed within two weeks, as a holiday programming project.

It aims to be easy and simple to use for C++ programming.

Design

DBL is a library and becomes an integral part of the application program. Unlike client–server model database management systems that are standalone process with which the application program communicates. The application software uses DBL's functionality through function calls.

Sample programs

Creating a simple database

This is a basic program that creates a simple database. However, as this task must be done usually once, it can be done by the DBL command-line interface.

#include"dbl.h"intmain(){path("D:\\");//set the path to the folder where the files will be storeddatabasedb("mydatabase");//mydatabase is the name of the databasedb.new_tab("customer");//create a new table called customer in the databasewrite(db);//write the database structure into a filecharpkey=1;table*tab=db.get_tab("customer");//get the table customer from the databasetab->add_col("cod",INTEGER,1,pkey);//add a column called cod to the table customertab->add_col("name",CHARACTER,32);//add a column called name to the table customertab->add_col("brithdate",INTEGER,3);tab->add_col("sex",CHARACTER,1);tab->add_col("phone",INTEGER,1);tab->set_structure();write(*tab);//write the table structure into filescreate_data_file(*tab);//create the data file of the table customerreturn0;}

Library structure

Class database

This class stores the database name and its tables. The main functions are:

char*name();//get the database namechar*name(char*dbname);//set the database namevoidnew_tab(char*tabname);//create a new tabletable*get_tab(char*tabname);//return the pointer to the table

Useful functions that use the class database are:

voidwrite(database&db);//write the database structure into a filefriendvoidread(database&db);//read the database structure from a filefriendvoiddel(database&db);//delete the database and its tables filesfriendvoidprint(database&db);//print the database on the screen

Class table

This class stores the table name and its structure, the columns of the table. The main functions are:

char*name();//get the table namechar*name(char*dbname);//set the table namevoidadd_col(column&c);//add a new column to the tablevoidadd_col(char*col_name,charcol_type,intcol_len=1,charpkey=0);column*get_col(intidx);//get the column by its indexcolumn*get_col(char*name);//get the column by its nameintnum_col();//get the number of columns in the table//finish the structure of the table.//This function must be called after adding all columns or after reading the structure of the table from a filevoidset_structure();rownew_row();//get a new row with the table structure

Useful functions that use the class table are:

voidwrite(table&t);//write the table structure into a filevoidread(table&t);//read the table structure from a filefriendvoiddel(table&t);//delete the table files, header and data filesvoidprint(table&t);//print the table on the screenfriendstd::ostream&operator<<(std::ostream&o,table&t);//print the table structureintnum_row(table&t);//get the number of rows in the data file of the table

Class row

This class stores the columns of the table and the data to be stored in the data file. The main functions are:

voidset(intidx,storage&s);//set the storage of a column by its indexvoidset(intidx,void*v);//set the value to be stored in a column by its indexstorage*get(intidx);//get the storage from the a column by its index

Useful functions that use the class row are:

voidwrite(table&t,row&r,intidx);//write the data in the data file of the tablevoidread(table&t,row&r,intidx);//read the data from the data file of the tablevoiddel(char*file,table&t,intidx);//delete the data from the data file of the table

Class storage

This class stores the column and a value for that column. The main functions are:

char*value();//get the value being stored by the objectvoidvalue(void*val);//set the value to be storedvoidvalue(char*val);//set the value to be stored, a C-style string and all functions of the class column.

Useful functions that use the class storage are:

intget_int(storage&s);//get the integer being storedcharget_char(storage&s);//get the char being storedboolget_bool(storage&s);//get the bool being storedfloatget_float(storage&s);//get the float being storeddoubleget_double(storage&s);//get the double being stored

Class column

This class stores the name and the structure of a column. The main functions are:

char*name();//get the name of the columnchar*name(char*n);//set the name of the columnchartype();//get the type of the columnchartype(chart);//set the type of the columnintlength();//get the length of the array that the column can holdintlength(intlen);//set the length of the array that the column can hold, len>0voidpkey(charb);//set if the column is the primary key or not (0 is false, 1 is true)charpkey();//get if the column is the primary key or notinttotal_size();//get the total size, in bytes, that the column can hold

Class index

This class stores the indexes of a table. The main functions are:

intseek(void*val);//look for a value in the indexesintseek(char*val);//look for a C-style string in the indexes

Useful functions that use the class index are:

voidwrite(table&t,index&idx);//write the indexes of a table into a filevoidread(index&idx);//read the indexes from a file

DBL command-line interface

By the DBL command-line interface program one can create a database, a table, and add columns to this table, besides other operations such as printing.

External links

• Official website