/**
* Given one xmldb_table and one xmldb_field, return the SQL statements needed to modify the default of the field in the table.
*
* @param xmldb_table $xmldb_table The table related to $xmldb_field.
* @param xmldb_field $xmldb_field The instance of xmldb_field to get the modified default value from.
* @return array The SQL statement for modifying the default value.
*/
public function getModifyDefaultSQL($xmldb_table, $xmldb_field)
{
$results = array();
/// Get the quoted name of the table and field
$tablename = $this->getTableName($xmldb_table);
$fieldname = $this->getEncQuoted($xmldb_field->getName());
/// Decide if we are going to create/modify or to drop the default
if ($xmldb_field->getDefault() === null) {
$results = $this->getDropDefaultSQL($xmldb_table, $xmldb_field);
//Drop
} else {
$results = $this->getCreateDefaultSQL($xmldb_table, $xmldb_field);
//Create/modify
}
return $results;
}
/**
* Given one xmldb_table and one xmldb_field, return the SQL statements needed to modify the default of the field in the table.
*
* @param xmldb_table $xmldb_table The table related to $xmldb_field.
* @param xmldb_field $xmldb_field The instance of xmldb_field to get the modified default value from.
* @return array The SQL statement for modifying the default value.
*/
public function getModifyDefaultSQL($xmldb_table, $xmldb_field)
{
// MSSQL is a bit special with default constraints because it implements them as external constraints so
// normal ALTER TABLE ALTER COLUMN don't work to change defaults. Because this, we have this method overloaded here
$results = array();
// Decide if we are going to create/modify or to drop the default
if ($xmldb_field->getDefault() === null) {
$results = $this->getDropDefaultSQL($xmldb_table, $xmldb_field);
//Drop but, under some circumstances, re-enable
$default_clause = $this->getDefaultClause($xmldb_field);
if ($default_clause) {
//If getDefaultClause() it must have one default, create it
$results = array_merge($results, $this->getCreateDefaultSQL($xmldb_table, $xmldb_field));
//Create/modify
}
} else {
$results = $this->getDropDefaultSQL($xmldb_table, $xmldb_field);
//Drop (only if exists)
$results = array_merge($results, $this->getCreateDefaultSQL($xmldb_table, $xmldb_field));
//Create/modify
}
return $results;
}
/**
* Given one xmldb_table and one xmldb_field, return the SQL statements needed to alter the field in the table.
*
* PostgreSQL has some severe limits:
* - Any change of type or precision requires a new temporary column to be created, values to
* be transfered potentially casting them, to apply defaults if the column is not null and
* finally, to rename it
* - Changes in null/not null require the SET/DROP NOT NULL clause
* - Changes in default require the SET/DROP DEFAULT clause
*
* @param xmldb_table $xmldb_table The table related to $xmldb_field.
* @param xmldb_field $xmldb_field The instance of xmldb_field to create the SQL from.
* @param string $skip_type_clause The type clause on alter columns, NULL by default.
* @param string $skip_default_clause The default clause on alter columns, NULL by default.
* @param string $skip_notnull_clause The null/notnull clause on alter columns, NULL by default.
* @return string The field altering SQL statement.
*/
public function getAlterFieldSQL($xmldb_table, $xmldb_field, $skip_type_clause = NULL, $skip_default_clause = NULL, $skip_notnull_clause = NULL)
{
$results = array();
// To store all the needed SQL commands
// Get the normal names of the table and field
$tablename = $xmldb_table->getName();
$fieldname = $xmldb_field->getName();
// Take a look to field metadata
$meta = $this->mdb->get_columns($tablename);
$metac = $meta[$xmldb_field->getName()];
$oldmetatype = $metac->meta_type;
$oldlength = $metac->max_length;
$olddecimals = empty($metac->scale) ? null : $metac->scale;
$oldnotnull = empty($metac->not_null) ? false : $metac->not_null;
$olddefault = empty($metac->has_default) ? null : $metac->default_value;
$typechanged = true;
//By default, assume that the column type has changed
$precisionchanged = true;
//By default, assume that the column precision has changed
$decimalchanged = true;
//By default, assume that the column decimal has changed
$defaultchanged = true;
//By default, assume that the column default has changed
$notnullchanged = true;
//By default, assume that the column notnull has changed
// Detect if we are changing the type of the column
if ($xmldb_field->getType() == XMLDB_TYPE_INTEGER && $oldmetatype == 'I' || $xmldb_field->getType() == XMLDB_TYPE_NUMBER && $oldmetatype == 'N' || $xmldb_field->getType() == XMLDB_TYPE_FLOAT && $oldmetatype == 'F' || $xmldb_field->getType() == XMLDB_TYPE_CHAR && $oldmetatype == 'C' || $xmldb_field->getType() == XMLDB_TYPE_TEXT && $oldmetatype == 'X' || $xmldb_field->getType() == XMLDB_TYPE_BINARY && $oldmetatype == 'B') {
$typechanged = false;
}
// Detect if we are changing the precision
if ($xmldb_field->getType() == XMLDB_TYPE_TEXT || $xmldb_field->getType() == XMLDB_TYPE_BINARY || $oldlength == -1 || $xmldb_field->getLength() == $oldlength) {
$precisionchanged = false;
}
// Detect if we are changing the decimals
if ($xmldb_field->getType() == XMLDB_TYPE_INTEGER || $xmldb_field->getType() == XMLDB_TYPE_CHAR || $xmldb_field->getType() == XMLDB_TYPE_TEXT || $xmldb_field->getType() == XMLDB_TYPE_BINARY || !$xmldb_field->getDecimals() || !$olddecimals || $xmldb_field->getDecimals() == $olddecimals) {
$decimalchanged = false;
}
// Detect if we are changing the default
if ($xmldb_field->getDefault() === null && $olddefault === null || $xmldb_field->getDefault() === $olddefault) {
$defaultchanged = false;
}
// Detect if we are changing the nullability
if ($xmldb_field->getNotnull() === $oldnotnull) {
$notnullchanged = false;
}
// Get the quoted name of the table and field
$tablename = $this->getTableName($xmldb_table);
$fieldname = $this->getEncQuoted($xmldb_field->getName());
// Decide if we have changed the column specs (type/precision/decimals)
$specschanged = $typechanged || $precisionchanged || $decimalchanged;
// if specs have changed, need to alter column
if ($specschanged) {
// Always drop any exiting default before alter column (some type changes can cause casting error in default for column)
if ($olddefault !== null) {
$results[] = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' DROP DEFAULT';
// Drop default clause
}
$alterstmt = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $this->getEncQuoted($xmldb_field->getName()) . ' TYPE' . $this->getFieldSQL($xmldb_table, $xmldb_field, null, true, true, null, false);
// Some castings must be performed explicitly (mainly from text|char to numeric|integer)
if (($oldmetatype == 'C' || $oldmetatype == 'X') && ($xmldb_field->getType() == XMLDB_TYPE_NUMBER || $xmldb_field->getType() == XMLDB_TYPE_FLOAT)) {
$alterstmt .= ' USING CAST(' . $fieldname . ' AS NUMERIC)';
// from char or text to number or float
} else {
if (($oldmetatype == 'C' || $oldmetatype == 'X') && $xmldb_field->getType() == XMLDB_TYPE_INTEGER) {
$alterstmt .= ' USING CAST(CAST(' . $fieldname . ' AS NUMERIC) AS INTEGER)';
// From char to integer
}
}
$results[] = $alterstmt;
}
// If the default has changed or we have performed one change in specs
if ($defaultchanged || $specschanged) {
$default_clause = $this->getDefaultClause($xmldb_field);
if ($default_clause) {
$sql = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' SET' . $default_clause;
// Add default clause
$results[] = $sql;
} else {
if (!$specschanged) {
// Only drop default if we haven't performed one specs change
$results[] = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' DROP DEFAULT';
// Drop default clause
}
}
}
// If the not null has changed
if ($notnullchanged) {
if ($xmldb_field->getNotnull()) {
$results[] = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' SET NOT NULL';
} else {
$results[] = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' DROP NOT NULL';
}
}
// Return the results
return $results;
}
/**
* Given one xmldb_table and one xmldb_field, return the SQL statements needed to alter the field in the table.
*
* Oracle has some severe limits:
* - clob and blob fields doesn't allow type to be specified
* - error is dropped if the null/not null clause is specified and hasn't changed
* - changes in precision/decimals of numeric fields drop an ORA-1440 error
*
* @param xmldb_table $xmldb_table The table related to $xmldb_field.
* @param xmldb_field $xmldb_field The instance of xmldb_field to create the SQL from.
* @param string $skip_type_clause The type clause on alter columns, NULL by default.
* @param string $skip_default_clause The default clause on alter columns, NULL by default.
* @param string $skip_notnull_clause The null/notnull clause on alter columns, NULL by default.
* @return string The field altering SQL statement.
*/
public function getAlterFieldSQL($xmldb_table, $xmldb_field, $skip_type_clause = NULL, $skip_default_clause = NULL, $skip_notnull_clause = NULL)
{
$skip_type_clause = is_null($skip_type_clause) ? $this->alter_column_skip_type : $skip_type_clause;
$skip_default_clause = is_null($skip_default_clause) ? $this->alter_column_skip_default : $skip_default_clause;
$skip_notnull_clause = is_null($skip_notnull_clause) ? $this->alter_column_skip_notnull : $skip_notnull_clause;
$results = array();
// To store all the needed SQL commands
// Get the quoted name of the table and field
$tablename = $this->getTableName($xmldb_table);
$fieldname = $xmldb_field->getName();
// Take a look to field metadata
$meta = $this->mdb->get_columns($xmldb_table->getName());
$metac = $meta[$fieldname];
$oldmetatype = $metac->meta_type;
$oldlength = $metac->max_length;
// To calculate the oldlength if the field is numeric, we need to perform one extra query
// because ADOdb has one bug here. http://phplens.com/lens/lensforum/msgs.php?id=15883
if ($oldmetatype == 'N') {
$uppertablename = strtoupper($tablename);
$upperfieldname = strtoupper($fieldname);
if ($col = $this->mdb->get_record_sql("SELECT cname, precision\n FROM col\n WHERE tname = ? AND cname = ?", array($uppertablename, $upperfieldname))) {
$oldlength = $col->precision;
}
}
$olddecimals = empty($metac->scale) ? null : $metac->scale;
$oldnotnull = empty($metac->not_null) ? false : $metac->not_null;
$olddefault = empty($metac->default_value) || strtoupper($metac->default_value) == 'NULL' ? null : $metac->default_value;
$typechanged = true;
//By default, assume that the column type has changed
$precisionchanged = true;
//By default, assume that the column precision has changed
$decimalchanged = true;
//By default, assume that the column decimal has changed
$defaultchanged = true;
//By default, assume that the column default has changed
$notnullchanged = true;
//By default, assume that the column notnull has changed
$from_temp_fields = false;
//By default don't assume we are going to use temporal fields
// Detect if we are changing the type of the column
if ($xmldb_field->getType() == XMLDB_TYPE_INTEGER && $oldmetatype == 'I' || $xmldb_field->getType() == XMLDB_TYPE_NUMBER && $oldmetatype == 'N' || $xmldb_field->getType() == XMLDB_TYPE_FLOAT && $oldmetatype == 'F' || $xmldb_field->getType() == XMLDB_TYPE_CHAR && $oldmetatype == 'C' || $xmldb_field->getType() == XMLDB_TYPE_TEXT && $oldmetatype == 'X' || $xmldb_field->getType() == XMLDB_TYPE_BINARY && $oldmetatype == 'B') {
$typechanged = false;
}
// Detect if precision has changed
if ($xmldb_field->getType() == XMLDB_TYPE_TEXT || $xmldb_field->getType() == XMLDB_TYPE_BINARY || $oldlength == -1 || $xmldb_field->getLength() == $oldlength) {
$precisionchanged = false;
}
// Detect if decimal has changed
if ($xmldb_field->getType() == XMLDB_TYPE_INTEGER || $xmldb_field->getType() == XMLDB_TYPE_CHAR || $xmldb_field->getType() == XMLDB_TYPE_TEXT || $xmldb_field->getType() == XMLDB_TYPE_BINARY || !$xmldb_field->getDecimals() || !$olddecimals || $xmldb_field->getDecimals() == $olddecimals) {
$decimalchanged = false;
}
// Detect if we are changing the default
if ($xmldb_field->getDefault() === null && $olddefault === null || $xmldb_field->getDefault() === $olddefault || "'" . $xmldb_field->getDefault() . "'" === $olddefault) {
//Equality with quotes because ADOdb returns the default with quotes
$defaultchanged = false;
}
// Detect if we are changing the nullability
if ($xmldb_field->getNotnull() === $oldnotnull) {
$notnullchanged = false;
}
// If type has changed or precision or decimal has changed and we are in one numeric field
// - create one temp column with the new specs
// - fill the new column with the values from the old one
// - drop the old column
// - rename the temp column to the original name
if ($typechanged || ($oldmetatype == 'N' || $oldmetatype == 'I') && ($precisionchanged || $decimalchanged)) {
$tempcolname = $xmldb_field->getName() . '___tmp';
// Short tmp name, surely not conflicting ever
if (strlen($tempcolname) > 30) {
// Safeguard we don't excess the 30cc limit
$tempcolname = 'ongoing_alter_column_tmp';
}
// Prevent temp field to have both NULL/NOT NULL and DEFAULT constraints
$skip_notnull_clause = true;
$skip_default_clause = true;
$xmldb_field->setName($tempcolname);
// Drop the temp column, in case it exists (due to one previous failure in conversion)
// really ugly but we cannot enclose DDL into transaction :-(
if (isset($meta[$tempcolname])) {
$results = array_merge($results, $this->getDropFieldSQL($xmldb_table, $xmldb_field));
}
// Create the temporal column
$results = array_merge($results, $this->getAddFieldSQL($xmldb_table, $xmldb_field, $skip_type_clause, $skip_type_clause, $skip_notnull_clause));
// Copy contents from original col to the temporal one
// From TEXT to integer/number we need explicit conversion
if ($oldmetatype == 'X' && $xmldb_field->GetType() == XMLDB_TYPE_INTEGER) {
$results[] = 'UPDATE ' . $tablename . ' SET ' . $tempcolname . ' = CAST(' . $this->mdb->sql_compare_text($fieldname) . ' AS INT)';
} else {
if ($oldmetatype == 'X' && $xmldb_field->GetType() == XMLDB_TYPE_NUMBER) {
$results[] = 'UPDATE ' . $tablename . ' SET ' . $tempcolname . ' = CAST(' . $this->mdb->sql_compare_text($fieldname) . ' AS NUMBER)';
// Normal cases, implicit conversion
} else {
$results[] = 'UPDATE ' . $tablename . ' SET ' . $tempcolname . ' = ' . $fieldname;
}
}
// Drop the old column
$xmldb_field->setName($fieldname);
//Set back the original field name
$results = array_merge($results, $this->getDropFieldSQL($xmldb_table, $xmldb_field));
// Rename the temp column to the original one
$results[] = 'ALTER TABLE ' . $tablename . ' RENAME COLUMN ' . $tempcolname . ' TO ' . $fieldname;
// Mark we have performed one change based in temp fields
$from_temp_fields = true;
// Re-enable the notnull and default sections so the general AlterFieldSQL can use it
$skip_notnull_clause = false;
$skip_default_clause = false;
// Disable the type section because we have done it with the temp field
$skip_type_clause = true;
// If new field is nullable, nullability hasn't changed
if (!$xmldb_field->getNotnull()) {
$notnullchanged = false;
}
// If new field hasn't default, default hasn't changed
if ($xmldb_field->getDefault() === null) {
$defaultchanged = false;
}
}
// If type and precision and decimals hasn't changed, prevent the type clause
if (!$typechanged && !$precisionchanged && !$decimalchanged) {
$skip_type_clause = true;
}
// If NULL/NOT NULL hasn't changed
// prevent null clause to be specified
if (!$notnullchanged) {
$skip_notnull_clause = true;
// Initially, prevent the notnull clause
// But, if we have used the temp field and the new field is not null, then enforce the not null clause
if ($from_temp_fields && $xmldb_field->getNotnull()) {
$skip_notnull_clause = false;
}
}
// If default hasn't changed
// prevent default clause to be specified
if (!$defaultchanged) {
$skip_default_clause = true;
// Initially, prevent the default clause
// But, if we have used the temp field and the new field has default clause, then enforce the default clause
if ($from_temp_fields) {
$default_clause = $this->getDefaultClause($xmldb_field);
if ($default_clause) {
$skip_notnull_clause = false;
}
}
}
// If arriving here, something is not being skipped (type, notnull, default), calculate the standard AlterFieldSQL
if (!$skip_type_clause || !$skip_notnull_clause || !$skip_default_clause) {
$results = array_merge($results, parent::getAlterFieldSQL($xmldb_table, $xmldb_field, $skip_type_clause, $skip_default_clause, $skip_notnull_clause));
return $results;
}
// Finally return results
return $results;
}
