7.3.40. object_exist¶
7.3.40.1. 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.
7.3.40.2. Syntax¶
This command takes only one required parameter:
object_exist name
7.3.40.3. 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.
7.3.40.4. Parameters¶
This section describes all parameters.
7.3.40.4.1. Required parameters¶
There is only one required parameter.
7.3.40.4.1.1. 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.
7.3.40.4.2. Optional parameters¶
There is no optional parameter.
7.3.40.5. 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.