ALTER TABLE

Версия 10:58, 7 октября 2009

ALTER TABLE table <operation> [, <operation> …];

<operation> = ADD <col_def>
| ADD <tconstraint>
| ALTER [COLUMN] column_name <alt_col_clause>
| DROP col
| DROP CONSTRAINT constraint

<alt_col_clause> = TO new_col_name
| TYPE new_col_datatype
| POSITION new_col_position

<col_def> = col {<datatype> | COMPUTED [BY] (<expr>) | domain}
[DEFAULT {literal | NULL | USER}]
[NOT NULL]

[<col_constraint>]
[COLLATE collation]

<datatype> =
{SMALLINT | INTEGER | FLOAT | DOUBLE PRECISION}[<array_dim>]
| (DATE | TIME | TIMESTAMP}[<array_dim>]
| {DECIMAL | NUMERIC} [(precision [, scale])] [<array_dim>]
| {CHAR | CHARACTER | CHARACTER VARYING | VARCHAR} [(int)]
[<array_dim>] [CHARACTER SET charname]
| {NCHAR | NATIONAL CHARACTER | NATIONAL CHAR}
[VARYING] [(int)] [<array_dim>]
| BLOB [SUB_TYPE {int | subtype_name}] [SEGMENT SIZE int]
[CHARACTER SET charname]
| BLOB [(seglen [, subtype])]<array_dim> = [[x:]y [, [x:]y …]]

<expr> = A valid SQL expression that results in a single value.

<col_constraint> = [CONSTRAINT constraint]
{ UNIQUE
| PRIMARY KEY
| REFERENCES other_table [(other_col [, other_col …])]
[ON DELETE {NO ACTION|CASCADE|SET DEFAULT|SET NULL}]
[ON UPDATE {NO ACTION|CASCADE|SET DEFAULT|SET NULL}]
| CHECK (<search_condition>)}

<tconstraint> = [CONSTRAINT constraint]
{{PRIMARY KEY | UNIQUE} (col [, col …])
| FOREIGN KEY (col [, col …])
REFERENCES other_table [(other_col [, other_col …])]
[ON DELETE {NO ACTION|CASCADE|SET DEFAULT|SET NULL}]
[ON UPDATE {NO ACTION|CASCADE|SET DEFAULT|SET NULL}]
| CHECK (<search_condition>)}

<search_condition> = <val> <operator> {<val> | (<select_one>)}
| <val> [NOT] BETWEEN <val> AND <val>
| <val> [NOT] LIKE <val> [ESCAPE <val>]
| <val> [NOT] IN (<val> [, <val> …] | <select_list>)
| <val> IS [NOT] NULL
| <val> {>= | <=}
| <val> [NOT] {= | < | >}
| {ALL | SOME | ANY} (<select_list>)
| EXISTS (<select_expr>)
| SINGULAR (<select_expr>)
| <val> [NOT] CONTAINING <val>
| <val> [NOT] STARTING [WITH] <val>
| (<search_condition>)
| NOT <search_condition>
| <search_condition> OR <search_condition>
| <search_condition> AND <search_condition>

<val> = { col [<array_dim>] | :variable
| <constant> | <expr> | <function>
| udf ([<val> [, <val> …]])
| NULL | USER | RDB$DB_KEY | ? }
[COLLATE collation]

<constant> = num | 'string' | charsetname 'string'

<function> = COUNT (* | [ALL] <val> | DISTINCT <val>)
| SUM ([ALL] <val> | DISTINCT <val>)
| AVG ([ALL] <val> | DISTINCT <val>)
| MAX ([ALL] <val> | DISTINCT <val>)
| MIN ([ALL] <val> | DISTINCT <val>)
| CAST (<val> AS <datatype>)
| UPPER (<val>)
| GEN_ID (generator, <val>)

<operator> = {= | < | > | <= | >= | !< | !> | <> | !=}

<select_one> = SELECT on a single column; returns exactly one value.

<select_list> = SELECT on a single column; returns zero or more values.

<select_expr> = SELECT on a list of values; returns zero or more values.