SQLJ host-expression

Syntax

Description

:

Indicates that the variable or expression that follows is a host expression. The colon must immediately precede the variable or expression.

IN|OUT|INOUT

For a host expression that is used as a parameter in a stored procedure call, identifies whether the parameter provides data to the stored procedure (IN), retrieves data from the stored procedure (OUT), or does both (INOUT). The default is IN.

simple-variable

Specifies a Java unqualified identifier.

complex-expression

Specifies a Java expression that results in a single value.

INDICATOR :simple-variable or INDICATOR :(complex-expression)

Specifies the optional indicator variable for the corresponding Java host variable. The data type of the indicator variable must be the Java short type. The only valid values for :simple-variable or :(complex-expression) are:

For customized applications, and for input, only these values are valid:

Indicator value	Equivalent constant	Meaning of value
-1	sqlj.runtime.ExecutionContext.DBNull	Null
-2, -3, -4, -6		Null
-5	sqlj.runtime.ExecutionContext.DBDefault	Default
-7	sqlj.runtime.ExecutionContext.DBUnassigned	Unassigned
short-value >=0	sqlj.runtime.ExecutionContext.DBNonNull	Non-null

For uncustomized applications, and for input, only these values are valid:

Indicator value	Equivalent constant	Meaning of value
-1	sqlj.runtime.ExecutionContext.DBNull	Null
-7 <= short-value < -1		Null
0	sqlj.runtime.ExecutionContext.DBNonNull	Non-null
short-value >0		Non-null

For customized or uncustomized applications, and for output, SQLJ sets one of these values:

Indicator value	Equivalent constant	Meaning of value
-1	sqlj.runtime.ExecutionContext.DBNull	Retrieved value is SQL NULL
0		Retrieved value is not SQL NULL

Usage notes

• A complex expression must be enclosed in parentheses.
• ANSI/ISO rules govern where a host expression can appear in a static SQL statement.
• Indicator variables are required in the following cases:
  • For input, when a Java primitive type is used to assign the NULL value to a table column.
  • For output, when a Java primitive type is used for a host variable, and the source column can return NULL values.

    If an SQL NULL value is returned, and no indicator variable is defined, an SQLNullException is thrown.

  Indicator variables are not required for input or output of a Java null value as an SQL NULL, if the data type of the host variable is:

  • The data type of a Java class
  • A custom database type that the driver supports
• , … variable-n
• For output, indicator variables are valid in the following types of statements:
  • CALL statement with OUT or INOUT parameters
  • FETCH positioned-iterator INTO variable-1, … variable-n
  • SELECT column-1, … column-n INTO variable-1, … variable-n