Libraries.Data.Database.DropTable Documentation
The DropTable class is a query to either remove a table from a database or to remove all data from it. DropTable contains only two attributes of importance, the name of the table to manipulate and whether or not we are deleting all of the data or the data and the table itself.
Example Code
use Libraries.Data.Database
DropTable table
table:SetTable("Users")
Inherits from: Libraries.Language.Object, Libraries.Data.Database.Query, Libraries.Data.Database.Support.RemappableName
Actions Documentation
AddNameRemap(text newName, Libraries.Data.Database.Support.RemappableName original)
Adds objects that have been remapped to single table for reference in actions called when building the query to text. Examples of RemappableNames are columns, tables, and subqueries.
Parameters
- text newName
- Libraries.Data.Database.Support.RemappableName
AddPreparedParameter(Libraries.Data.Database.Support.Parameter param)
At the plugin level prepared statements are used to add a layer of security from injection attacks. Every parameter in the prepared paramter array will be stripped from the actual query text and set appropriately at the plugin level.
Parameters
AddSubquery(text name, Libraries.Data.Database.Find subquery)
Adds a subquery to this query. Only Find queries are supported for now. A Subquery is a query that exists another outer query. An example could be a Find where the table to search through is actually the result of another query.
Parameters
- text name
- Libraries.Data.Database.Find
AddTableNameRemap(text table, text newName)
This adds a name that can be used in the place of a table. This action does not set the table of this query but only a name that can be referenced if the table is added.
Parameters
- text table: The name of the table to set for this query
- text newName
Example
use Libraries.Data.Database.Find
Find query
query:SetTable("orders", "o")
query:AddTableNameRemap("members", "m")
query:AddInnerJoin("m", "o:name = m:name")
AddTableReference(text table)
Internal. Queries keep track of what tables are referenced to check for ambiguous column names
Parameters
- text table
Compare(Libraries.Language.Object object)
This action compares two object hash codes and returns an integer. The result is larger if this hash code is larger than the object passed as a parameter, smaller, or equal. In this case, -1 means smaller, 0 means equal, and 1 means larger. This action was changed in Quorum 7 to return an integer, instead of a CompareResult object, because the previous implementation was causing efficiency issues.
Parameters
- Libraries.Language.Object: The object to compare to.
Return
integer: The Compare result, Smaller, Equal, or Larger.
Example
Object o
Object t
integer result = o:Compare(t) //1 (larger), 0 (equal), or -1 (smaller)
ConvertToStructuredQueryLanguage()
Return
text
EmptyPreparedParameters()
Clears the prepared parameter list. Necessary because running a query again without emptying the list will cause the list of parameters to not shrink
EmptyTableReferences()
Empties the table references hash table.
Equals(Libraries.Language.Object object)
This action determines if two objects are equal based on their hash code values.
Parameters
- Libraries.Language.Object: The to be compared.
Return
boolean: True if the hash codes are equal and false if they are not equal.
Example
use Libraries.Language.Object
use Libraries.Language.Types.Text
Object o
Text t
boolean result = o:Equals(t)
Filter(text value)
Some queries make use of the filter which is an expression checked against the values of the columns in the rows of a database table. The filter is written using Quorum syntax and will be type checked to see if it's valid. Column names can be used and the names made by the user using name remaps. An example filter would be "priority < 4" where priority is a column that exists and can be mapped to an integer.
Parameters
- text value: The expression to be used in the query
Example
use Libraries.Data.Database.Delete
Delete query
query:SetTable("orders")
query:Filter("priority < 4")
GetDatabaseMetaData()
GetHashCode()
This action gets the hash code for an object.
Return
integer: The integer hash code of the object.
Example
Object o
integer hash = o:GetHashCode()
GetNameRemaps()
Grabs the table containing all aliases that have been set in this query
Return
GetPreparedParameters()
Used at the plugin level to get all parameters that need to be set in the prepared statement
Return
GetRawFilter()
Returns the filter as given by the user. The filter will be converted to a syntax accepted by the database server and this action returns whatever the user originally typed
Return
text:
GetRemappedName()
Returns the alias
Return
text:
GetTable()
Returns the table this query is meant to be ran against
Return
text:
GetTableReferences()
Internal. Used by other actions to grab what tables are referenced to check if column names are valid.
Return
GetTranslatedFilter()
Returns the filter as translated by the quorum compiler. The filter will be converted to a syntax accepted by the database server and this action returns whatever the user originally typed
Return
text:
IsEmptyTableOnly()
If this flag is true, when issued this DropTable query will drop the data inside the table, but not the table itself. This is equivalent to the TRUNCATE command in Structured Query Language (SQL).
Return
boolean:
SetDatabaseMetaData(Libraries.Data.Database.DatabaseMetaData meta)
Sets the DatabaseMetaData for this query. This is necessary for checking things like if a table referenced exists or if a filter has valid column references.