7.3.41. object_exist
#
7.3.41.1. Summary#
New in version 5.0.6.
object_exist
returns whether object with the specified name exists
or not in database.
It’s a light operation. It just checks existence of the name in the database. It doesn’t load the specified object from disk.
object_exist
doesn’t check object type. The existing object may be
table, column, function and so on.
7.3.41.2. Syntax#
This command takes only one required parameter:
object_exist name
7.3.41.3. Usage#
You can check whether the name is already used in database:
Execution example:
object_exist Users
# [[0,1337566253.89858,0.000355720520019531],false]
table_create Users TABLE_HASH_KEY ShortText
# [[0,1337566253.89858,0.000355720520019531],true]
object_exist Users
# [[0,1337566253.89858,0.000355720520019531],true]
The object_exist Users
returns false
before you create
Users
table.
The object_exist Users
returns true
after you create Users
table.
7.3.41.4. Parameters#
This section describes all parameters.
7.3.41.4.1. Required parameters#
There is only one required parameter.
7.3.41.4.1.1. name
#
Specifies the object name to be checked.
If you want to check existence of a column, use
TABLE_NAME.COLUMN_NAME
format like the following:
Execution example:
table_create Logs TABLE_NO_KEY
# [[0,1337566253.89858,0.000355720520019531],true]
column_create Logs timestamp COLUMN_SCALAR Time
# [[0,1337566253.89858,0.000355720520019531],true]
object_exist Logs.timestamp
# [[0,1337566253.89858,0.000355720520019531],true]
Logs
is table name and timestamp
is column name in
Logs.timestamp
.
7.3.41.4.2. Optional parameters#
There is no optional parameter.
7.3.41.5. Return value#
The command returns true
as body if object with the specified name
exists in database such as:
[HEADER, true]
The command returns false
otherwise such as:
[HEADER, false]
See Output format for HEADER
.