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Pragmas

In LiteDB v5, pragmas are variables that can alter the behavior of a datafile. They are stored in the header of the datafile.

Name Read-only Data type Description Default value
USER_VERSION no int Reserved for version control by the user. Does not affect the behavior of the datafile. 0
COLLATION yes (can be changed with a rebuild) string (internally stored as int) Check Collation. CurrentCulture and IgnoreCase
TIMEOUT no int Maximum amount of time (in seconds) that the engine waits for a shared resouce to be unlocked. 60
LIMIT_SIZE no long Maximum size (in bytes) that the datafile can grow to. Cannot be smaller than the current datafile size. Cannot be smaller than 4 pages (32768 bytes). long.MaxValue
UTC_DATE no bool If false, dates are converted to local time on retrieval. Storage format is not affected (always in UTC). false
CHECKPOINT no int Maximum number of pages to be stored in the log before a soft checkpoint. If set to 0, auto-checkpoint and shutdown checkpoint are disabled. 1000

Examples

  • select pragmas from $database; returns the pragmas in the current datafile

  • pragma USER_VERSION = 1; sets USER_VERSION to 1

  • pragma UTC_DATE = true; sets UTC_DATE to true

Rebuild Options

Rebuild options are used to configure a rebuild.

Name Data type Description Default value
collation string Check Collation. null (will use CurrentCulture and IgnoreCase if null)
password string Defines the password for an encrypted datafile. null (datafile will not be encrypted)

If the rebuild command is issued without options, both are assumed to be null.

Rebuilds are also useful to defragment a datafile, making it smaller and faster to access.

  • rebuild; rebuilds the database with the default collation and no password
  • rebuild {"collation": "en-GB/IgnoreCase"}; rebuilds the datafile with the en-GB culture and case-insensitive string comparison
  • rebuild {"collation": "en-GB/IgnoreCase", "password" : "1234"}; rebuilds the datafile with the en-GB culture, case-insensitive string comparison and sets the password to “1234”