/*
* pg_get_serverdef_string finds the foreign server that corresponds to the
* given foreign tableId, and returns this server's definition.
*/
char *
pg_get_serverdef_string(Oid tableRelationId)
{
ForeignTable *foreignTable = GetForeignTable(tableRelationId);
ForeignServer *server = GetForeignServer(foreignTable->serverid);
ForeignDataWrapper *foreignDataWrapper = GetForeignDataWrapper(server->fdwid);
StringInfoData buffer = { NULL, 0, 0, 0 };
initStringInfo(&buffer);
appendStringInfo(&buffer, "CREATE SERVER %s", quote_identifier(server->servername));
if (server->servertype != NULL)
{
appendStringInfo(&buffer, " TYPE %s",
quote_literal_cstr(server->servertype));
}
if (server->serverversion != NULL)
{
appendStringInfo(&buffer, " VERSION %s",
quote_literal_cstr(server->serverversion));
}
appendStringInfo(&buffer, " FOREIGN DATA WRAPPER %s",
quote_identifier(foreignDataWrapper->fdwname));
/* append server options, if any */
AppendOptionListToString(&buffer, server->options);
return (buffer.data);
}
/*
* pg_get_tableschemadef_string returns the definition of a given table. This
* definition includes table's schema, default column values, not null and check
* constraints. The definition does not include constraints that trigger index
* creations; specifically, unique and primary key constraints are excluded.
*/
static char *
pg_shard_get_tableschemadef_string(Oid tableRelationId)
{
Relation relation = NULL;
char *relationName = NULL;
char relationKind = 0;
TupleDesc tupleDescriptor = NULL;
TupleConstr *tupleConstraints = NULL;
int attributeIndex = 0;
bool firstAttributePrinted = false;
AttrNumber defaultValueIndex = 0;
AttrNumber constraintIndex = 0;
AttrNumber constraintCount = 0;
StringInfoData buffer = { NULL, 0, 0, 0 };
/*
* Instead of retrieving values from system catalogs as other functions in
* ruleutils.c do, we follow an unusual approach here: we open the relation,
* and fetch the relation's tuple descriptor. We do this because the tuple
* descriptor already contains information harnessed from pg_attrdef,
* pg_attribute, pg_constraint, and pg_class; and therefore using the
* descriptor saves us from a lot of additional work.
*/
relation = relation_open(tableRelationId, AccessShareLock);
relationName = generate_relation_name(tableRelationId);
relationKind = relation->rd_rel->relkind;
if (relationKind != RELKIND_RELATION && relationKind != RELKIND_FOREIGN_TABLE)
{
ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("%s is not a regular or foreign table", relationName)));
}
initStringInfo(&buffer);
if (relationKind == RELKIND_RELATION)
{
appendStringInfo(&buffer, "CREATE TABLE %s (", relationName);
}
else
{
appendStringInfo(&buffer, "CREATE FOREIGN TABLE %s (", relationName);
}
/*
* Iterate over the table's columns. If a particular column is not dropped
* and is not inherited from another table, print the column's name and its
* formatted type.
*/
tupleDescriptor = RelationGetDescr(relation);
tupleConstraints = tupleDescriptor->constr;
for (attributeIndex = 0; attributeIndex < tupleDescriptor->natts; attributeIndex++)
{
Form_pg_attribute attributeForm = tupleDescriptor->attrs[attributeIndex];
if (!attributeForm->attisdropped && attributeForm->attinhcount == 0)
{
const char *attributeName = NULL;
const char *attributeTypeName = NULL;
if (firstAttributePrinted)
{
appendStringInfoString(&buffer, ", ");
}
firstAttributePrinted = true;
attributeName = NameStr(attributeForm->attname);
appendStringInfo(&buffer, "%s ", quote_identifier(attributeName));
attributeTypeName = format_type_with_typemod(attributeForm->atttypid,
attributeForm->atttypmod);
appendStringInfoString(&buffer, attributeTypeName);
/* if this column has a default value, append the default value */
if (attributeForm->atthasdef)
{
AttrDefault *defaultValueList = NULL;
AttrDefault *defaultValue = NULL;
Node *defaultNode = NULL;
List *defaultContext = NULL;
char *defaultString = NULL;
Assert(tupleConstraints != NULL);
defaultValueList = tupleConstraints->defval;
Assert(defaultValueList != NULL);
defaultValue = &(defaultValueList[defaultValueIndex]);
defaultValueIndex++;
Assert(defaultValue->adnum == (attributeIndex + 1));
Assert(defaultValueIndex <= tupleConstraints->num_defval);
/* convert expression to node tree, and prepare deparse context */
defaultNode = (Node *) stringToNode(defaultValue->adbin);
defaultContext = deparse_context_for(relationName, tableRelationId);
/* deparse default value string */
defaultString = deparse_expression(defaultNode, defaultContext,
false, false);
appendStringInfo(&buffer, " DEFAULT %s", defaultString);
}
/* if this column has a not null constraint, append the constraint */
if (attributeForm->attnotnull)
{
appendStringInfoString(&buffer, " NOT NULL");
}
}
}
/*
* Now check if the table has any constraints. If it does, set the number of
* check constraints here. Then iterate over all check constraints and print
* them.
*/
if (tupleConstraints != NULL)
{
constraintCount = tupleConstraints->num_check;
}
for (constraintIndex = 0; constraintIndex < constraintCount; constraintIndex++)
{
ConstrCheck *checkConstraintList = tupleConstraints->check;
ConstrCheck *checkConstraint = &(checkConstraintList[constraintIndex]);
Node *checkNode = NULL;
List *checkContext = NULL;
char *checkString = NULL;
/* if an attribute or constraint has been printed, format properly */
if (firstAttributePrinted || constraintIndex > 0)
{
appendStringInfoString(&buffer, ", ");
}
appendStringInfo(&buffer, "CONSTRAINT %s CHECK ",
quote_identifier(checkConstraint->ccname));
/* convert expression to node tree, and prepare deparse context */
checkNode = (Node *) stringToNode(checkConstraint->ccbin);
checkContext = deparse_context_for(relationName, tableRelationId);
/* deparse check constraint string */
checkString = deparse_expression(checkNode, checkContext, false, false);
appendStringInfoString(&buffer, checkString);
}
/* close create table's outer parentheses */
appendStringInfoString(&buffer, ")");
/*
* If the relation is a foreign table, append the server name and options to
* the create table statement.
*/
if (relationKind == RELKIND_FOREIGN_TABLE)
{
ForeignTable *foreignTable = GetForeignTable(tableRelationId);
ForeignServer *foreignServer = GetForeignServer(foreignTable->serverid);
char *serverName = foreignServer->servername;
appendStringInfo(&buffer, " SERVER %s", quote_identifier(serverName));
AppendOptionListToString(&buffer, foreignTable->options);
}
relation_close(relation, AccessShareLock);
return (buffer.data);
}
