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en:guides:database [2013/04/30 22:06]
linea
en:guides:database [2014/11/09 17:55] (current)
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 This installs the sqlite client in your /usr/bin directory. The version offered with slitaz is a stable release but not the latest one available. SQLite is under active development and new versions appear on a regular basis. If you need a more recent version you may use the precompiled binary which is available on the SQLite.org download page. To do this, you can simply download the precompiled binary and save it in the /usr/bin/ folder, overwriting the file from the tazpkg installation if it exists. ​ This installs the sqlite client in your /usr/bin directory. The version offered with slitaz is a stable release but not the latest one available. SQLite is under active development and new versions appear on a regular basis. If you need a more recent version you may use the precompiled binary which is available on the SQLite.org download page. To do this, you can simply download the precompiled binary and save it in the /usr/bin/ folder, overwriting the file from the tazpkg installation if it exists. ​
-<note important>​ The version of the SQLite client is only backwards compatible with the database file. You cannot access a database which was created using for example ​version 3.7.16.2 with an older release of the client like 3.7.9. The opposite - a newer version of the client accessing a database which was created with a previous version ​is generally possible. This can be relevant if you need to access a database from different client systems. Best practice is to use the same version of the client everywhere. </​note>​+<note important>​ The version of the SQLite client is only backwards compatible with the database file. You cannot access a database which was created usingfor exampleversion 3.7.16.2 with an older release of the client like 3.7.9. The opposite - a newer version of the client accessing a database which was created with a previous version ​though ​is generally possible. This can be relevant if you need to access a database from different client systems. Best practice is to use the same version of the client everywhere. </​note>​
  
 To run SQLite with Perl, one additional package must be installed; the perl-sqlite module: To run SQLite with Perl, one additional package must be installed; the perl-sqlite module:
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 The sqlite client /​usr/​bin/​sqlite3 allows you to do anything from the command line which also can be done using Perl, Python or any other language. You can print, update, add or delete records and manipulate columns and tables. ​ The sqlite client /​usr/​bin/​sqlite3 allows you to do anything from the command line which also can be done using Perl, Python or any other language. You can print, update, add or delete records and manipulate columns and tables. ​
-Starting the program without any parameters or options returns a > prompt. You may enter sql commands terminated by the semicolon (;) as is normal in all sql dialects. ​Query'​s ​must contain a reference to the database file and the sql part must be between double quotes and terminated by a semicolon (;). +Starting the program without any parameters or options returns a > prompt. You may enter sql commands terminated by the semicolon (;) as is normal in all sql dialects. ​Queries ​must contain a reference to the database file and the sql part must be between double quotes and terminated by a semicolon (;). 
 One small example: <​code>​sqlite3 /​home/​tux/​yourdatabase "​select * from sqlite_master;"</​code>​ One small example: <​code>​sqlite3 /​home/​tux/​yourdatabase "​select * from sqlite_master;"</​code>​
 This command prints the layout of the tables in the database. To create a new database, set the filename to whatever is deemed suitable. A new database is created if the file does not exist. ​ This command prints the layout of the tables in the database. To create a new database, set the filename to whatever is deemed suitable. A new database is created if the file does not exist. ​
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 The filesize depends heavily on the type of database and its actual contents. The more data is entered, the larger the file becomes. ​ The filesize depends heavily on the type of database and its actual contents. The more data is entered, the larger the file becomes. ​
 Please note that the file does not shrink when a large amount of data is deleted. Instead, the empty space is preserved and re-used before the file starts to increase in size again. ​ Please note that the file does not shrink when a large amount of data is deleted. Instead, the empty space is preserved and re-used before the file starts to increase in size again. ​
-Something else to keep in mind is that the file permissions must be set correctly to be able read or write the database. ​+Something else to keep in mind is that the file permissions must be set correctly to be able to read or write the database. ​ 
 + 
 +======Keeping sqlite up-to-date====== 
 +SQLite is still under development and new versions are made available every one-two months. You can run the latest client without compiling and installing a package every time. In the end, it is just one binary file: sqlite3. This file is available as a precompiled binary for download from www.sqlite.org. All that's needed is to move it to the correct folder, thereby replacing the old version. A sample script to automate this action could look like this: 
 +<​code>​cd /​home/<​your-home-dir>​ 
 +if [ -s sqlite3 ]; then 
 + rm sqlite3.old 
 + mv /​usr/​bin/​sqlite3 sqlite3.old 
 + mv sqlite3 /usr/bin/ 
 + chmod 755 /​usr/​bin/​sqlite3 
 +fi 
 +</​code>​ 
 +This script looks for a file named sqlite3 in /​home/<​your-home-dir>,​ if found it moves the old sqlite3 binary to sqlite3.old in /​home/<​your-home-dir>​ and installs the latest version with the correct access mode in /usr/bin.  
 
en/guides/database.1367352411.txt.gz · Last modified: 2013/04/30 22:06 by linea